Through the Agency's NPDES permit regulations, EPA interpreted the CWA to allow best management practices (BMPs) to take the place of numeric effluent limitations under certain circumstances. Federal regulations at 40 CFR §122.44(k), entitled "Establishing limitations, standards, and other permit conditions (applicable to state NPDES programs ...)," provides that permits may include BMPs to control or abate the discharge of pollutants when: (1) "[a]uthorized under section 402(p) of the CWA for the control of stormwater discharges"; or (2) "[n]umeric effluent limitations are infeasible." 40 CFR § 122.44(k).
Courts have held that the CWA does not require EPA to set numeric limitations where such limits are infeasible. Citizens Coal Council v. EPA, 447 F.3d 879, 895-96 (6[th] Cir. 2006). The Sixth Circuit cited Waterkeeper Alliance, Inc. v. EPA, 399 F.3d 486, 502 (2[nd] Cir. 2005), stating "site-specific BMPs are effluent limitations under the CWA." Additionally, the Sixth Circuit cited Natural Res. Def. Council, Inc. v. EPA, 673 F.2d 400, 403 (D.C.Cir.1982) noting that "section 502(11) [of the CWA] defines `effluent limitation' as `any restriction' on the amounts of pollutants discharged, not just a numerical restriction."
For the draft 2021 PGP, EPA is using the term "Pest Management Measures," as defined in Appendix A of the draft 2021 PGP, to represent those practices used to meet the non-numeric effluent limitations.
EPA's Decision to Include Non-Numeric Technology-Based Effluent Limitations in the Draft 2021 PGP and Rationale for Why the Limits Represent the Appropriate (BPT, BCT, or BAT) Level of Control.
As described above, numeric effluent limitations are not always feasible because the discharges of pollutants pose challenges not presented by other types of NPDES-regulated discharges of pollutants. The technology-based effluent limitations remain unchanged from EPA's 2016 PGP. The technology-based effluent limitations in this permit are non-numeric based on the following facts:
The point in time for which a numeric effluent limitation would apply is not easily determinable. For discharges of pollutants from the application of pesticides, the discharges of pollutants can be highly intermittent with those discharges of pollutants not practically separable from the pesticide application itself. For example, the discharge from the application of a chemical pesticide to waters of the United States is a discharge of pollutants when there is a residual remaining in the ambient water after the pesticide is no longer serving its intended purpose (i.e., acting as a pesticide against targeted pests in the applied medium). This discharge of pollutants also will have combined with any other discharges of pollutants to that waterbody (be it from other point sources, non-point source runoff, air deposition, etc.). Given this situation, it is not clear what would be measured for a numeric limit or when.
For discharges from the application of pesticides, there are often many short durations, highly variable, pollutant discharges to surface waters from many different locations for which it would be difficult to establish a numeric limitation at each location. This variability makes setting reasonable and fair numeric effluent limitations for pesticide applications extremely difficult. Even in a normal plant specific setting, EPA takes into account the variability of pollutant removal performance at a facility operated in compliance with applicable statutory and regulatory requirements to derive technology-based limitations. In the water-quality based effluent limitations context, EPA takes into account ambient conditions of the waterbody which can require complex modelling and formulas to derive what discharge of pollutant level is necessary, without being overly stringent, to protect water quality. In the context of pesticide application, the numbers of variables that would affect such a calculation becomes unworkable. In this situation, requiring the use of standard control practices (i.e., narrative non-numeric effluent limitations), provides a reasonable approach to control pesticide discharges of pollutants.
The precise location for which a numeric effluent limitation would apply is not clear. Discharges from the application of pesticides are different from discharges of pollutants of process wastewater from a particular industrial or commercial facility where the effluent is more predictable and easily identified as an effluent from a conveyance (e.g., pipe or ditch), can be precisely measured for compliance prior to discharge, and can be more effectively analyzed to develop numeric effluent limitations.
EPA does not have sufficient information to develop numeric effluent limitations at this time. To develop numeric technology-based effluent limitations, EPA must evaluate factors outlined in 40 CFR 125.3, such as the age of equipment and facilities involved, the process employed, the potential process changes, and non-water quality environmental impacts. In addition, EPA estimates that more than 400 pesticide active ingredients contained in over 3,500 pesticide products may be covered under this permit.
In the context of this general permit, EPA has determined these non-numeric effluent limits represent the best practicable technology (BPT) for all pollutants, the best conventional pollutant control technology for conventional pollutants (BCT) and the best available technology economically achievable (BAT) for toxic and non-conventional pollutants. EPA has determined that the combination of pollution reduction practices described below are the most environmentally sound way to control the point source discharges of biological pesticides, and chemical pesticides that leave a residue.
Technology-based effluent limitations in this permit are presented specific to each pesticide use pattern to reflect the variations in procedures and expectations for the use and application of pesticides. These non-numeric effluent limitations are expected to reduce the point source discharges of pollutants to waters of the United States, thereby protecting the receiving waters, including to the extent necessary to meet applicable water quality standards. EPA notes that the draft 2021 PGP uses the term "Pest Management Measures." Use of the term Pest Management Measures is intended to better describe the range of pollutant reduction practices that may be employed when applying pesticides, whether they are structural, non-structural or procedural and includes BMPs as one of the components.
The BAT/BPT/BCT effluent limitations in this permit are expressed as specific pollution prevention requirements for minimizing the pollutant levels in the discharge. In the context of this general permit, these requirements represent the best technologically available and economically practicable and achievable controls. EPA has determined that the combination of pollution prevention approaches and structural management practices required by these limits are the most environmentally sound way to control the discharge of pollutants to meet the effluent limitations. Pollution prevention continues to be the cornerstone of the NPDES program.
Requirements are technologically available
EPA has found that the requirements of this permit represent the appropriate level of control representing BPT, BCT, and BAT. The draft 2021 PGP requires certain Operators to implement Pest Management Measures to meet the technology-based effluent limitations that are based on IPM principles. See further discussion of pest management measures below. Unlike other general permits, the technology available to Operators depends on the type of Operator (e.g. Applicator v. Decision-maker). For this reason, technology-based effluent limitations vary depending on Operator type. As an example of an effluent limit that meets BPT and BAT standards, applicators are required to maintain pesticide application equipment in proper operating condition, including requirement to calibrate, clean, and repair such equipment and prevent leaks, spills, or other unintended discharges. This effluent limitation is not appropriate for decision-makers that do not apply the pesticide themselves and as such, is not an effluent limitation for decision-makers. EPA determined that calibrating, cleaning, and repairing pesticide application equipment is technologically available and based on EPA's evaluation of this industry, is currently being implemented by many operators and is a practice that every operator should be doing when using pesticides, as a way to prevent leaks, spills, and other unintended discharges, such as over-applying pesticides as a result of poorly maintained equipment.
Requirements meet the BPT and BAT economic tests set forth in the CWA
There are different economic considerations under BPT, BCT, and BAT. EPA finds that the limits in the draft 2021 PGP meet the BPT and BAT economic tests. Because the types of controls under consideration minimize toxic, nonconventional, and conventional pollutants, conventional pollutants are controlled by the same practices that control toxic and nonconventional pollutants. Hence, EPA is evaluating effluent limits using a BPT and a BAT standard, but since conventional pollutants will also be adequately controlled by these same effluent limits for which EPA applied the BPT and BAT tests, EPA has determined that it is not necessary to conduct BCT economic tests.
Under BPT, EPA has determined that the requirements of this draft 2021 PGP are economically practicable since they contain the same requirements as found in the 2011 PGP and the 2016 PGP. To make the original BPT determination, EPA considered the reasonableness of the relationship between the costs of application of technology in relation to the effluent reduction benefit derived. CWA section 301(b)(1)(B); 40 CFR 125.3(d)(1). This analysis was documented in the fact sheet accompanying the 2011 PGP (available at https://downloads.regulations.gov/EPA-HQ-OW-2010-0257-1276/content.pdf). EPA estimates that the proposed 2021 PGP will cover approximately 14,300 Operators. In light of the original BPT determination and the fact that the draft 2021 PGP does not alter per entity compliance costs, EPA finds that the BPT limits have a cost that is justified by the effluent reduction resulting from the BPT effluent limitations and that for BAT, the costs are economically achievable because they can reasonably be borne by the industry as a whole.
EPA continues to study the efficacy of various types of pollution prevention measures and BMPs; however, for this permit numeric limitations are still not feasible.
Requirements have acceptable non-water quality environmental impacts.
EPA finds that the controls in the permit have acceptable non-water quality environmental impacts. Because the draft 2021 PGP contains the same requirements as the 2016 PGP there are no significant changes to the non-water quality environmental impacts. EPA also notes that the requirement to comply with the FIFRA label incorporates the consideration of the environmental impacts of the pesticide's use with the benefits of the pesticide's use. When EPA determines that a pesticide product can be registered for use, the Agency has concluded that the use of the pesticide product will not cause unreasonable adverse effects to humans or the environment when applied according to the label directions and restrictions. "Unreasonable adverse effects" takes into account the economic, social, and environmental costs and benefits of the use of the pesticide. EPA finds that the pollutant discharges authorized by this permit have recreational, environmental or other human benefits. For example, permittees will discharge pollutants to control for mosquitos and other flying insects in order to prevent the spread of infectious diseases, such as malaria, vesicular stomatitis, and West Nile Virus. Control of weed, algae, and plant pathogens promotes healthy aquatic communities and recreational and other benefits for the human population. Permittees will also discharge pollutants to control invasive and nuisance aquatic animals, such as fish, lampreys, and mollusks, which negatively affect aquatic biodiversity, human health, and economic stability. Pollutant discharges will also control pests that threaten the health of the forest canopy, such as the gypsy moth. This permit includes permit terms which provide reasonable protection to impacted waters of the United States without constraining the use of these pesticides which provide acceptable non-water quality environmental impacts.
Pest Management Measures Used to Meet the Technology-Based Effluent Limitations
Just as there is variability in the pesticide applications as described above, there is variability in the Pest Management Measures that can be used to meet the effluent limitations. Therefore, EPA is not mandating the specific Pest Management Measures Operators must implement to meet the limitations. This is analogous to an industrial situation where discharges of pollutants to waters of the United States are via pipes and a numeric effluent limitation may be specified as a given quantity of pollutant that may be discharged, but EPA would not specify what technology should be employed to meet that limitation. For pesticides, namely mosquitocides, for example, Part 2.2.1.b of the draft 2021 PGP requires mosquito control Decision-makers to consider mechanical/physical methods of control to eliminate or reduce mosquito habitat. How this is achieved will vary by Operator: For some, this may be achieved through elimination of development habitat (e.g. filling low areas, dredging, etc.) while for others these measures will not be feasible. Thus, a given Pest Management Measure may be acceptable and appropriate in some circumstances but not in others. In this respect, the non-numeric effluent limitations in the draft 2021 PGP are similar to performance-based numeric effluent limitations, which also do not require specific control technologies as long as the limitations are met.
Pest Management Measures can be actions (including processes, procedures, schedules of activities, prohibitions on practices, and other management practices), or structural or installed devices to prevent or reduce water pollution. The key is determining what measure is appropriate for the situation in order to meet the effluent limitation. In this permit, Operators are required to implement site-specific Pest Management Measures to meet these effluent limitations. The permit along with this fact sheet provide examples of Pest Management Measures, but Operators must tailor these to their situations as well as improve upon them as necessary to meet the effluent limitations.
The approach to Pest Management Measures in this permit is consistent with the CWA as well as its implementing regulations at 40 CFR 122.44(k)(4). Section 402(a)(2) of the CWA states: "The administrator shall prescribe conditions for such permits to assure compliance with the requirements in paragraph (1) . . . including conditions on data and information collection, reporting and such other requirements as he deems appropriate." (Section 402(a)(1) includes effluent limitation requirements.) This statutory provision is reflected in the CWA implementing regulations, which state that BMPs (in this case, specifically Pest Management Measures) can be included in permits when, "[t]he practices are reasonably necessary to achieve effluent limitations and standards or to carry out the purposes and intent of the CWA." 40 CFR 122.44(k)(4).
Implementation of Pest Management Measures
Part 2.0 of the draft 2021 PGP requires Operators to implement Pest Management Measures to meet the technology-based effluent limitations listed in that Part. It also provides Operators with important considerations for the implementation of their specific Pest Management Measures. Some Decision-makers will have to document how such factors were taken into account in the implementation of their Pest Management Measures (See Part 5 of the draft 2021 PGP). EPA recognizes that not all of these considerations will be applicable to every pest management area nor will they always affect the choice of Pest Management Measures. EPA expects that Operators have the experience and working knowledge to apply pesticides properly. The draft 2021 PGP requires the Operator to apply such expertise and working knowledge to use best professional judgment in meeting the permit terms. If Operators find their Pest Management Measures are not minimizing discharges of pollutants adequately, the Pest Management Measures must be modified as expeditiously as practicable. See Part 6 of the draft 2021 PGP, Corrective Action.
EPA recognizes that Operators need the flexibility to tailor Pest Management Measures to their situation as well as improve upon them as necessary to meet the technology-based effluent limitations. Decision-makers will tailor Pest Management Measures based on available information and the best professional judgment of qualified personnel. For example, while Part 2.2 of the draft 2021 PGP requires Decision-makers to evaluate other means than pesticide use, the Decision-makers ultimately decide what ultimate pest control method is employed. Thus, while mechanical pest removal or less toxic chemicals may be possible options, the Decision-maker is in the best position to know what method is most appropriate and effective against the target pest.
Pest Management Measures and Technology-Based Effluent Limitations  -  Definition of "Minimize"
EPA has found that the requirements of the draft 2021 PGP represent the appropriate BPT, BCT and BAT level of control. The non-numeric effluent limitations require Operators to "minimize" discharges of pollutants. Consistent with the control level requirements of the CWA, the term "minimize" means to reduce and/or eliminate pollutants discharges to waters of the United States through the use of Pest Management Measures to the extent technologically available and economically achievable and practicable. For many pesticide applications, minimization of the discharge of pesticides to waters of the United States can be achieved without using highly engineered, complex pest control systems. The specific limits included in Part 2.0 of the draft 2021 PGP emphasize effective "low-tech" approaches, including using only the amount of pesticide product and frequency of pesticide application necessary to control the target pest, performing equipment maintenance and calibration, assessing weather conditions prior to pesticide application, accurately identifying the pest problem, efficiently and effectively managing the pest problem, and properly using pesticides.
Statutes, Regulations, and Other Requirements
In addition to the applicable permit requirements, Operators must comply with all applicable statutes, regulations and other requirements including, but not limited to, requirements contained in the labeling of pesticide products approved under FIFRA ("FIFRA labeling"). See Part 1.5 of the draft 2021 PGP. See also Part 2.0 ("As stated in Part 1.5, this permit requires all Operators to comply with all other applicable federal or state laws and regulations that pertain to application of pesticides by the Operator.").  Although the FIFRA label and labeling requirements are not effluent limitations, it is illegal to use a registered pesticide inconsistent with its labeling. In fact, Operators discharging under EPA's PGP must comply with FIFRA labeling requirements in order to be in compliance with the PGP technology-based effluent limits. Per parts 2.1 and 2.2 of the draft 2021 PGP, "To meet the effluent limitations of this permit, all Applicators [or Decision-makers] must implement Part 2.1 [or Part 2.2] to minimize the discharge of pesticides to waters of the United States from the application of pesticides, through the use of Pest Management Measures, as defined in Appendix A." Per Appendix A, Pest Management Measure means "any practice used to meet the effluent limitations that comply with manufacturer specifications, industry standards and recommended industry practices related to the application of pesticides, relevant legal requirements and other provisions that a prudent Operator would implement to reduce and/or eliminate pesticide discharges to waters of the United States." Pest Management Measures include FIFRA labeling requirements. Therefore, if Operators apply a pesticide in a manner inconsistent with any relevant water-quality related FIFRA labeling requirements such as those relating to application sites, rates, frequency, and methods, as well as provisions concerning proper storage and disposal of pesticide wastes and containers, the Operators would be in violation of the effluent limitation to minimize pesticides entering the waters of the United States. For example, an Operator, who is a pesticide Applicator, decides to use a mosquito adulticide pesticide product with a FIFRA label that contains the following language, "Apply this product at a rate not to exceed one pound per acre." The Applicator applies this product at higher than the allowable rate, which results in excess product being discharged into waters of the United States. EPA would find that this application was a misuse of the pesticide under the FIFRA label. Because of the misuse the Agency might also determine that the effluent limitation that requires the Operator to minimize discharges of pollutants to waters of the United States was violated, depending on the specific facts and circumstances. Therefore, pesticide use inconsistent with certain FIFRA labeling requirements could result in the Operator being held liable for a CWA violation as well as a FIFRA violation.
Technology-Based Effluent Limitations in the PGP
In the draft 2021 PGP, all Operators are classified as either "Applicators" or "Decision-makers" or both. An Applicator is an entity who performs the application of a pesticide or who has day-to-day control of the application (i.e., they are authorized to direct workers to carry out those activities) that results in a discharge to waters of the United States. A Decision-maker is an entity with control over the decision to perform pesticide applications, including the ability to modify those decisions that result in discharges of pollutants to waters of the United States. As such, more than one Operator may be responsible for compliance with this permit for any single discharge from the application of pesticides. EPA has delineated the non-numeric effluent limitations into tasks that EPA expects the Applicator to perform and tasks that EPA expects the Decision-maker to perform. In doing so, EPA has assigned the Applicator and the Decision-maker different responsibilities.
2.1	Applicators' Responsibilities
Part 2.1 of the draft 2021 PGP contains the general technology-based effluent limitations that all Applicators must perform, regardless of pesticide use pattern. These effluent limitations are generally preventative in nature and are designed to minimize pesticide discharges into waters of the United States. All Applicators are required to minimize the discharge of pesticides to waters of the United States by doing the following:
2.1.1	To the extent not determined by the Decision-maker, use only the amount of pesticide and frequency of pesticide application necessary to control the target pest, using equipment and application procedures appropriate for this task.
As noted earlier, it is illegal to use a pesticide in any way prohibited by the FIFRA labeling. Also, use of pesticides must be consistent with any other applicable state or federal laws. To minimize the total amount of pesticide discharged, Operators must use only the amount of pesticide and frequency of pesticide application necessary to control the target pest. Using only the amount of pesticide and frequency of pesticide application needed ensures maximum efficiency in pest control with the minimum quantity of pesticide. Using only the amount and frequency of applications necessary can result in cost and time savings to the user. To minimize discharges of pollutants, Operators should base the rate and frequency of application on what is known to be effective against the target pest.
2.1.2	Maintain pesticide application equipment in proper operating condition, including requirement to calibrate, clean, and repair such equipment and prevent leaks, spills, or other unintended discharges.
Common-sense and good housekeeping practices enable pesticide users to save time and money and reduce the potential for unintended discharge of pesticides to waters of the United States. Regular maintenance activities should be practiced and improper pesticide mixing, and equipment loading should be avoided. When preparing the pesticides for application be certain that you are mixing them correctly and preparing only the amount of material that you need. Carefully choose the pesticide mixing and loading area and avoid places where a spill will discharge into waters of the United States. Some basic practices Operators should consider are:
Inspect pesticide containers at purchase to ensure proper containment;
Maintain clean storage facilities for pesticides;
Regularly monitor containers for leaks;
Rotate pesticide supplies to prevent leaks that may result from long term storage; and
Promptly deal with spills following manufacturer recommendations.
To minimize discharges of pollutants, Applicators must ensure that the rate of application is calibrated (i.e. nozzle choice, droplet size, etc.) to deliver the appropriate quantity of pesticide needed to achieve greatest efficacy against the target pest. Improperly calibrated pesticide equipment may cause either too little or too much pesticide to be applied. This lack of precision can result in excess pesticide being available or result in ineffective pest control. When done properly, equipment calibration can assure uniform application to the desired target and result in higher efficiency in terms of pest control and cost. It is important for Applicators to know that pesticide application efficiency and precision can be adversely affected by a variety of mechanical problems that can be addressed through regular calibration. Sound maintenance practices to consider are:
Choosing the right spray equipment for the application
Ensuring proper regulation of pressure and choice of nozzle to ensure desired application rate
Calibrating spray equipment prior to use to ensure the rate applied is that required for effective control of the target pest
Cleaning all equipment after each use and/or prior to using another pesticide unless a tank mix is the desired objective and cross contamination is not an issue
Checking all equipment regularly (e.g., sprayers, hoses, nozzles, etc.) for signs of uneven wear (e.g., metal fatigue/shavings, cracked hoses, etc.) to prevent equipment failure that may result in inadvertent discharge into the environment
Replacing all worn components of pesticide application equipment prior to application.
2.1.3	Assess weather conditions (e.g. temperature, precipitation, and wind speed) in the treatment area to ensure application is consistent with all applicable federal requirements.
Weather conditions may affect the results of pesticide application. Applicators must assess the treatment area to determine whether weather conditions support pest populations and are suitable for pesticide application.
2.2	Decision-makers' Responsibilities
As noted above, NPDES permits must contain technology-based effluent limitations. Part 2.2 of the draft 2021 PGP contains the effluent limitations that Decision-makers must perform. The draft 2021 PGP requires all Decision-makers, to the extent Decision-makers determine the amount of pesticide or frequency of pesticide application, to minimize the discharge of pesticides to waters of the United States from the application of pesticides, through the use of Pest Management Measures, as defined in Appendix A of the draft 2021 PGP, by using only the amount of pesticide and frequency of pesticide application necessary to control the target pest.
In addition, Part 2.2 of the draft 2021 PGP requires that any Decision-maker who is required to submit a Notice of Intent (NOI) to identify the pest problem, implement effective and efficient pest management options, and adhere to certain pesticide use provisions. (For purposes of the discussion below on Part 2.2 of the draft 2021 PGP, the term Decision-maker means any Decision-maker who is or will be required to submit an NOI.) Parts 2.2.1  -  2.2.4 of the draft 2021 PGP do not apply to Decision-makers who will need to submit an NOI only because they discharge pollutants to waters of the United States containing NMFS Listed Resources of Concern and whose: (1) Pesticide application activities for which permit coverage is being requested will discharge pollutants to one or more receiving waters of the United States containing NMFS Listed Resources of Concern, but consultation with NMFS under Section 7 of the ESA has been concluded for pesticide application activities covered under this permit; or (2) Pesticide application activities for which permit coverage is being requested will discharge pollutants to one or more waters of the United States containing NMFS Listed Resources of Concern, but all "take" of these resources associated with such pesticide application activities has been authorized through NMFS' issuance of a permit under Section 10 of the ESA, and such authorization addresses the effects of the pesticide discharges and discharge-related activities on federally-listed species and federally-designated critical habitat. However, these Decision-makers must comply with all applicable conditions and/or requirements resulting from ESA Section 7 consultation or ESA Section 10 permit.
Decision-makers are required to perform each of these permit conditions prior to the first pesticide application covered under this permit and at least once each calendar year thereafter. These additional technology-based effluent limitations are based on integrated pest management principles. EPA is requiring certain Decision-makers to also comply with a different technology-based effluent limitation than Applicators because the Agency has determined that they are the Best Available Technology Economically Achievable for these Operators. These requirements are aimed at reducing discharge of pesticides to waters of the United States and lessening the adverse effects of pesticides that are applied. Each pesticide use pattern has specific limitations, and these requirements are divided into three different sections: (1) identify the problem, (2) pest management options, and (3) pesticide use. For each pest management area, Decision-makers must identify the problem prior to pesticide application, consider using a combination of chemicals and non-chemical Pest Management Measures, and perform surveillance before pesticide application to reduce environmental impacts.
EPA is requiring these additional technology-based effluent limitation requirements from Decision-makers and not the Applicators because the measures necessary to meet these requirements are within the control of the Decision-makers, not the Applicators.
As stated above, these technology-based effluent limitations are based on integrated pest management principles. Integrated pest management, as defined in FIFRA, is a sustainable approach to managing pests by combining biological, cultural, physical, and chemical tools in a way that minimizes economic, health, and environmental risks. (FIFRA, 7 U.S.C. 136r-1) Integrated pest management is not a single pest control method but, rather, a series of pest management evaluations, decisions and controls. In evaluating available and relevant information, EPA found that some commercial (For-Hire Applicators) and non-commercial (e.g., state governments, federal governments, local governments, utilities) entities are currently implementing integrated pest management or components of integrated pest management to minimize pesticide use. For example, federal agencies are required to implement integrated pest management under 7 USC 136r-1, "Federal agencies shall use Integrated Pest Management techniques in carrying out pest management through procurement and regulatory policies, and other activities." In addition, Executive Order 13514 (October 5, 2009) requires the head of each federal agency to implement integrated pest management and other appropriate landscape management practices as a means to promote pollution prevention and eliminate waste.
Below is a general discussion describing the limitations for all pesticide use patterns. Following the general discussion are more detailed descriptions of each specific requirement under each pesticide use pattern.
Any Decision-maker who is or will be required to submit an NOI must do the following regardless of the pesticide use pattern, except those Decision-makers who will need to submit an NOI only because they discharge pollutants to waters of the United States containing NMFS Listed Resources of Concern and that also comply with provisions in Part 1.6 of the draft 2021 PGP:
Identify the Problem
Decision-makers are required to identify the pest problem, identify the target pest, and establish an action threshold. Understanding the pest biology and ecology will provide insight into selecting the most effective and efficient Pest Management Measures (pesticidal or non-pesticidal methods), and in developing an action threshold. Action threshold is defined in Appendix A of the draft 2021 PGP as the point at which pest populations or environmental conditions cannot be tolerated, necessitating that pest control action be taken based on economic, human health, aesthetic, or other effects. An action threshold helps determine both the need for control actions and the proper timing of such actions. It is a predetermined pest level that is deemed to be unacceptable. In some situations, the action threshold for a pest may be zero (i.e., no presence of the pest is tolerated). This is especially true when the pest is capable of transmitting a human pathogen (e.g., mosquitoes and the West Nile virus) and/or is an invasive species. In areas where aquatic weeds are problematic, it may be preferable to use an aquatic herbicide as a preventive measure rather than after weeds become established. In some situations, even a slight amount of pest damage may be unacceptable for ecological or aesthetic reasons. Sometimes pre-emergent pesticide application is needed, as a preventive measure to keep aquatic weeds at bay. Action thresholds, often expressed as number of pests per unit area, can vary by pest, by site, and by season. In a new pest management program, action thresholds may be difficult to establish and as a practical approach should first focus on major pests. As Operators gain insight and experience into specific pest management settings, the action levels can be revised up or down.
To identify the problem at a treatment area, Decision-makers may use existing data to meet the conditions of this permit. For example, a mosquito district may use surveillance data from an adjacent district to identify pests in their pest management area. Decision-makers may also use relevant historical site data.
Pest Management Options
Decision-makers are required to implement efficient and effective means of Pest Management Measures that most successfully minimize discharges of pollutants to waters of the United States resulting from the application of pesticides. Decision-makers must evaluate both pesticide and non-pesticide methods. Decision-makers must consider and evaluate the following options: no action, prevention, mechanical/physical methods, cultural methods, biological control agents, and pesticides. In the evaluation of these options, Decision-makers must consider impacts to water quality, impacts to non-target organisms, feasibility, and cost effectiveness. Combinations of various management options are frequently the most effective Pest Management Measures over the long term. The goal should be to emphasize long-term control rather than a temporary fix. For additional information, see discussion under each pesticide use pattern.
Pesticide Use
Decision-makers are required to conduct pest surveillance in an area that is representative of the pest problem and reduce the impact on the environment. Pest surveillance is important to properly time the need for pest control. To reduce the impact on the environment and non-target organisms, Operators are required to only apply pesticides when the action threshold has been met. As noted earlier, action thresholds help determine both the need for control actions and the proper timing of such actions.
There are additional requirements designed for each pesticide use pattern in Parts 2.2.1 through 2.2.4 of the draft 2021 PGP. For additional information and other limits on pesticide use, see specific discussion under each pesticide use pattern.
2.2.1	Mosquito and Other Flying Insect Pests Control
Part 2.2.1.a -- Identify the Problem
Prior to the first pesticide application covered under this permit that will result in a discharge to waters of the United States, and at least once each calendar year thereafter prior to the first pesticide application for that calendar year, any Decision-maker who is or will be required to submit an NOI must do the following for each pest management area, as defined in Appendix A. Decision-makers must identify the pest problem in their pest management areas prior to the first application covered under the permit. Knowledge of the pest problem is an important step to developing Pest Management Measures. Re-evaluation of the pest problem is also important to ensure Pest Management Measures are still applicable. Decision-makers must identify the pest problem at least once each calendar year prior to the first application for that calendar year.
Establish densities for larval and adult mosquito or flying insect pest populations or identify environmental condition(s), either current or based on historical data, to serve as action threshold(s) for implementing Pest Management Measures. Decision-makers must develop action thresholds for larval and adult mosquitoes prior to the first pesticide application covered under this permit. The action thresholds must be re-evaluated at least once each calendar year. As noted in the general discussion above, an action threshold is a point at which pest populations or environmental conditions indicate that pest control action must be taken. Action thresholds help determine both the need for control actions and the proper timing of such actions. For example, an action threshold could be the number and distribution of service requests received from the public. It is a predetermined pest level (or other indicator) that is deemed to be unacceptable. For example, in Maryland, "A collection of more than 10 anthropophagous (human biting) female mosquitoes per night of trap operation is considered to be the level which causes discomfort and/or complaints from the majority of people. The light trap action threshold for ground spraying of adult mosquitoes is 10-20 per trap-night. The action threshold to suppress pest populations of adult mosquitoes by aerial spraying (application of insecticide by an aircraft) is a light trap collection of 100 female mosquitoes. The action threshold for landing rate counts to justify ground spraying for the control of adult mosquitoes is 3 mosquitoes in 2 minutes. The action threshold for aerial spraying is 12 mosquitoes per minute." For larvae control, action thresholds are determined by standard mosquito dipping techniques. For example, in Canyon County Mosquito Abatement District, Idaho, they established larvae density action levels for Culex species (primary disease vectors) as Low: 1-5 larvae per dip; Medium: 6-10 larvae per dip; High: > than 10 larvae per dip. The larvae density action threshold can be used to determine how much larval control products are to be used or even if any action is to be taken. In some situations, the action threshold for a pest may be zero (i.e., no presence of the pest is tolerated). This is especially true when the pest is capable of transmitting a human pathogen (e.g., mosquitoes and the West Nile virus).
Identify the target pest(s) to develop Pest Management Measures based on developmental and behavioral considerations for each pest. Knowledge of the developmental biology of mosquitoes is essential to developing Pest Management Measures for mosquito control.
Prior to the first pesticide application covered under the permit, Operators must ensure proper identification of mosquito to better understand the biology of the target pest and develop Pest Management Measures. Due to the great variability in developmental habitats and adult feeding behaviors as discussed previously, proper identification is imperative in designing an effective and efficient Pest Management Measures. Identification of the target pest will aid in development of Pest Management Measures aimed at both the immature and adult developmental stages. Identification of the target pest for a specific area allows 1) identification of potential breeding sites, 2) evaluation of alternative Pest Management Measures aimed at controlling the immature stages (habitat modification, source reduction, larvicides, biological larvicides, and oils), and 3) assessment of potential for disease transmission.
Similarly, for black flies, prior to first pesticide application covered under this permit, Operators must ensure proper identification of the pest to develop Pest Management Measures. Due to preferred hosts and developmental habitats, proper identification of the pest is instrumental in determining the biology (univoltine or multivoltine), and developmental habitat preference (e.g., flow rate, stream size, stream substrate composition), and flight range of the target pest. By knowing these factors, a control program can 1) determine if the black fly species warrants control activities (i.e. host preference and historical problems), 2) identify habitats and delineate the potential area for ongoing monitoring and control activities, 3) determine frequency of site monitoring, 4) estimate timing for pesticide application (i.e. historical seasonal occurrence, age distribution of susceptible immature population, environmental conditions suitable for control activity, etc.), 5) reduce discharge of pesticides into waters of the United States.

Identify known breeding sites for source reduction, larval control program, and habitat management. Once pests have been identified, mapping is a valuable tool in assessing mosquito habitats and designing control programs for a specific area to minimize pesticide discharges into waters of the United States. Maps may simply be township/city/county maps but may also include aerial photo assessments, topographic maps, and satellite imagery where available and/practicable. Mapping is essential to identify pest producing areas which can and cannot be controlled using non-chemical preventative measures (e.g., source reduction). Maps should include all potential sites for mosquito development including agricultural areas in the specific area (e.g., hay, pasture, circle irrigation, orchards, rill irrigated field crops, and flood irrigated pastures and farmland). Mapping should also be a priority in a surveillance program utilizing mosquito traps, biting counts, complaints, and reports from the public. Planning in coordination with mapping ensures the best Pest Management Measures (whether source reduction, biological, or chemical) for each particular pest is chosen. Operators must identify known breeding sites prior to the first pesticide application covered under this permit.
In conjunction with identifying the target pest, mapping should be considered part of control programs aimed at black fly management. As black flies are strong fliers and will travel great distance to obtain a blood meal, mapping should be for an extended area from the site to be protected by control activities. Pest identification and mapping should also be a priority in a surveillance program (both current and historical) to determine the need for initiating control activity. Identification and mapping are both essential to planning a control program which reduces pesticide discharges into waters of the United States.
Analyze existing surveillance data to identify new or unidentified sources of mosquito or flying insect pest problems as well as sites that have recurring pest problems. As discussed above, mapping is a valuable tool in assessing mosquito habitats and designing control programs. Decision-makers must analyze existing surveillance data to identity any new source of pest problems.
In the event there are no data for the pest management area in the past calendar year, use other available data as appropriate to meet the permit conditions in Part 2.2.1.a. Decision-makers may use historical data or neighboring district data to identify the pest and establish action thresholds.
Part 2.2.1.b -- Pest Management Options
Prior to the first pesticide application covered under this permit that will result in a discharge to waters of the United States, and at least once each calendar year thereafter prior to the first pesticide application for that calendar year, any Decision-maker who is or will be required to submit NOIs must select and implement efficient and effective means of Pest Management Measures that minimize discharges resulting from the application of pesticides to control mosquitoes or other flying insect pests. In developing the Pest Management Measures for each pest management area, the Decision-maker must evaluate the following management options, including a combination of these management options, considering impact to water quality, impact to non-target organisms, feasibility, and cost effectiveness: No action; Prevention; Mechanical/physical methods; Cultural methods; Biological control agents; and Pesticides. Decision-makers are required to evaluate management options and implement Pest Management Measures to minimize pesticide discharges into waters of the United States prior to the first pesticide application covered under this permit. For black flies, Pest Management Measures will vary by locality (i.e. stream size, stream substrate, and stream vegetation), black fly species (5 multi/univoltine development and host specificity), and financial concerns (i.e. accessibility to streams and size/rate of flow for the streams). As noted above, combinations of various management options are frequently the most effective Pest Management Measures over the long term. The goal should be to emphasize long-term control rather than a temporary fix. Decision-makers must reevaluate every year prior to the first pesticide application for that calendar year.
Based on problem identification, two preventive measures other than pesticides should be evaluated for black flies. The first is reducing the number of black fly breeding areas. This may include removal (physical and/or chemical) of vegetation and other objects in streams to reduce number of larval habitats. The second is temporary damming of flowing stream larval development sites to create pool habitats. As larvae require flowing water for development, pooling can kill developing black fly larvae. However, the impact of these habitat management options must be considered in relation to other environmental impacts on other aquatic species. Furthermore, due to the wide variability in stream size/flow rate and the accessibility of streams for habitat modification, these options are seldom acceptable control solutions for most black fly developmental habitats.
The following describes the management options that must be evaluated.
No Action. No action is to be taken, although a mosquito problem has been identified. This may be appropriate in cases where, for example, available control methods may cause secondary or non-target impacts that are not justified, or no control methods exist.
Prevention. Prevention strategies are program activities which eliminate developing mosquito populations through environmental modification and/or habitat management. For mosquito control, these activities are physical methods such as habitat modification, cultural methods that reduce sources of mosquitoes, and biological control.
Mechanical/Physical Methods. Habitat modification, also known as physical or permanent control, is in many cases the most effective mosquito control technique available and is accomplished by eliminating mosquito breeding sites. Habitat modification activities have the potential to be both effective and economical in some areas and can virtually eliminate the need for pesticide use in and adjacent to the affected habitat. However, the ability to use prevention strategies is dependent upon local authority and restrictions.
Cultural Methods. Cultural methods can reduce sources of mosquitoes and can be as simple as properly discarding old containers that hold water capable of producing Aedes aegypti, Ae. albopictus or Culex spp. or as complex as implementing Rotational Impoundment Management (RIM) or Open Marsh Water Management (OMWM) techniques. RIM is a source reduction strategy that controls salt marsh mosquitoes (e.g., Ae. taeniorhynchus and Ae. sollicitans) at the same time as significant habitat restoration is occurring. Source reduction may include; water management, vegetation management, biological control, and pesticide use in non-waters of the United States.
Containers provide excellent habitats for development of numerous mosquito species. These may include but are not limited to flowerpots, cans, and tires. Container-inhabiting mosquitoes of particular concern include, Ae. aeypti, Ae. albopictus, Cx. p. pipiens, and Cx. salinarious. A container-breeding mosquito problem can be solved by properly disposing of such materials, covering them, tipping them over to ensure that they do not collect water, and/or periodic draining. Urban container-breeding mosquito control is best implemented through education and surveillance programs.
Source reduction in freshwater lakes, ponds, and retention areas is more applicable to artificially created areas than natural areas. Artificial ponds can be eliminated as a breeding site simply by filling in the areas, (i.e. habitat modification). However, large permanent water bodies and areas for stormwater or wastewater retention require other methods. Options for these areas include minimizing and/or eliminating emergent and standing vegetation, maintenance of steep banks, and inclusion of deep-water areas as sanctuary for larvivorous fish.
Mosquito production from stormwater/wastewater habitats can result in considerable mosquito problems as a result of engineering, poor construction or improper maintenance. However, mosquito populations can typically be managed by keeping such areas free of weeds through an aquatic plant management program and maintaining water quality that can support larvivorous fish. Culex, Coquillettidia, Mansonia, and Anopheles mosquitoes are often produced in these habitats.
Pastures and agricultural lands are enormous mosquito producers, frequently generating huge broods of Aedes, Psorophora, and Culex mosquitoes. Improved drainage is one effective tool for source reduction in such habitats. The second is the use of efficient, precision irrigation practices that will result in less standing water for those agricultural areas that require artificial watering.
In coastal areas with extensive coastal salt marshes, there can be tremendous production of Aedes mosquitoes, making coastal human habitation virtually impossible. Several source reduction efforts can greatly reduce salt-marsh mosquito production through high-to mid-intensity management that relies upon artificial manipulation of the frequency and duration of inundation.
Biological Control Agents. The use of biological organisms or their byproducts to combat pest insects, such as mosquitoes, is termed biological control, or biocontrol. Biocontrol is utilization of parasites, predators, and pathogens to regulate pest populations. Generally, this definition includes natural and genetically modified organisms and means that the agent must be alive and able to attack the mosquito. The overall premise is simple: Biocontrol agents that attack mosquitoes naturally are grown in the lab and then released into the environment, usually in far greater numbers than they normally occur, and often in habitats that previously were devoid of them, so as to control targeted mosquito species.
One advantage of biocontrol agents is host-specificity which affords minimal disturbance to non-target species and to the environment. However, it is this specificity and the cost of commercializing biocontrol agents that deter development of biocontrol agents. In addition, utilization of biocontrol requires increased capital outlay and start-up costs as well as increased training requirements for personnel.
Biocontrol should be considered a set of tools that a mosquito control program can use when it is economically feasible. When combined with conventional chemicals and physical control procedures, biocontrol agents can provide short and, occasionally, long-term control. Biocontrol, as a conventional control method, should aim at the weakest link of the life cycle of the mosquito. In most cases, this is the larval life stage.
Mosquitofish (Gambusia affinis) are currently the most extensively used biocontrol agent. These fish, which feed on mosquito larvae, can be placed in a variety of permanent and semi-permanent water habitats. Differences of opinion exist on the utility and actual control benefits derived from Gambusia implementation in an integrated pest management program with results reported from excellent control to no control at all. Concerns over placing Gambusia in habitats where other fish species assemblages are threatened have been ongoing. Care must be taken in placement of this cosmopolitan species in areas where endemic fish species are sensitive to further environmental perturbation. Additionally, use of endemic fish species in these areas of concern deserves greater attention.
In some aquatic habitats, fish function as an excellent mosquito biocontrol mechanism. These typically are permanent habitats where Culex and Anopheles are the primary mosquito residents and where the mosquito densities are not excessive. However, in habitats such as salt marshes fish are unable to control the sudden explosion of larvae produced by rainfall or rising tides. Here, the mosquito population numerically exceeds what the fish can consume during the brief immature mosquito developmental period. In salt marshes, fish must rely on things other than mosquito larvae for their nutritional needs most of the time, simply because there may be long delays between hatches of larvae. Mosquito larvae present an abundant food source, but only for a few days during their rapid development.
Species of predacious mosquitoes in the genus Toxorhynchites have been studied in a variety of urban areas for control of container-inhabiting mosquitoes, such as the Asian tiger mosquito (Ae. albopictus). Toxorhynchites mosquitoes also affect mosquito populations that develop in the treehole environment; however, their introduction into urban container habitats has proven unsuccessful.
In specific containers, Toxorhynchites may consume a large number of prey mosquito larvae, such as Aedes aegypti and Ae. albopictus. However, this predator does not disperse well enough to impact the vast number of natural and artificial containers used by these mosquitoes. Additionally, their life-cycle is two to three times that of their prey making it impossible for them to keep up with the other more rapidly developing mosquitoes.
Another group of biocontrol agents with promise for mosquito control is the predacious copepods (very small crustaceans). Copepods can be readily mass reared, are easily to delivered to the target sites, and perform well when used with insecticides.
Birds and bats are often promoted as potential biocontrol agents of adult mosquitoes. However, while both predators eat adult mosquitoes, they do not do so in sufficient amounts to impact the mosquito populations. Mosquitoes provide such a small amount of nutrition that birds or bats expel more energy pursuing and eating mosquitoes than they derive from them. They are not a primary food source for these predators. Additionally, with mosquito flight behavior being crepuscular they are not active during the feeding periods of most birds. While bats are active during the correct time period, they simply cannot impact the massive numbers of adult mosquitoes available.
Bio-rational products exploit insecticidal toxins found in certain naturally occurring bacteria. These bacteria are cultured in mass and packaged in various formulations. The bacteria must be ingested by mosquito larvae, so the toxin is released. Therefore bio-rational products are only effective against larvae since pupae do not feed. The bacteria used to control mosquito larvae have no significant effects on non-target organisms. The possibility of creating a new invasive species by the introduction of biocontrols should be considered, evaluated, and avoided.
Pesticides. There are chemical and biological pesticide products registered for use against mosquitoes. Two biological pesticide products that are used against mosquito larvae singly or in combination are Bacillus thuringiensis israelensis (Bti) and Bacillus sphaericus (Bs). Manufactured Bti contains dead bacteria and remains effective in the water for 24 to 48 hours; some slow release formulations provide longer control. In contrast, Bs products contain live bacteria that in favorable conditions remain effective for more than 30 days. Both products are safe enough to be used in water that is consumed by humans. In addition to the biological pesticides, there are chemical pesticides for use against mosquitoes. As described below, once the determination is made to use pesticides to control mosquitoes, additional requirements under the 2016 PGP must be met.
Part 2.2.1.c. -- Pesticide Use
Conduct larval and/or adult surveillance in an area that is representative of the pest problem or evaluate existing larval surveillance data, environmental conditions, or data from adjacent area prior to each pesticide application to assess the pest management area and to determine when action threshold(s) is met. Pest surveillance is important for timing pest control properly and to evaluate the potential need for pesticide use for mosquito control. Understanding surveillance data may enable mosquito control Operators to more effectively target their control efforts. Decision-makers are required to conduct a surveillance program to minimize discharges of pollutants from control activities. Surveillance is necessary not only to establish pests' presence and abundance but also as an evaluation tool of the effectiveness of source reduction and chemical control activities. Furthermore, surveillance should be used as an indicator of the need for additional chemical control activities based on pre-established criteria related to population densities in local areas.
Larval surveillance involves routine sampling of aquatic habitats for developing mosquitoes. The primary tools used to determine larval densities and species composition are a calibrated dip cup and/or a bulb syringe for inaccessible areas such as treeholes. The counts may be expressed as the number of immature (larvae and pupae) mosquitoes per dip, per unit volume, or per unit surface area of the site. However, due to natural mortality from environmental factors, disease and predators, larval dip counts do not provide an accurate indication of the potential adult population. Nevertheless, larval counts do indicate when chemical larval control measures are warranted.
Adult surveillance is a key component of Pest Management Measures. Adult surveillance can be conducted using a variety of methods including but not limited to CDC traps, New Jersey light traps, resting site traps, egg oviposition traps, vehicle traps, and landing count rates. Mosquito control Operators should use a variety of the available traps as adults are attracted to different traps depending on their species, sex, and physiological condition. Trapped adults provide information about local species composition, distribution, and density. In addition, the need for adulticide application may also be established through the number and distribution of service requests received from the public. Collection data also provide feedback to the mapping and planning component of the integrated pest management program as well as to its effectiveness and also serve to identify new sources of mosquitoes or identify recurring problem sites.
Disease surveillance, where practical, is also a key component of Pest Management Measures. Detecting antibodies in "sentinel" chicken flocks, equine cases, and testing dead birds and adult mosquitoes for infections are all used to determine whether disease is being transmitted in an area. Mosquito and vector control agencies also may test mosquitoes for viruses in their laboratories. Although generally less sensitive than sentinel chickens, mosquito infections may be detected earlier in the season than chicken seroconversions and therefore provide an early warning of virus activity. However, disease surveillance is not applicable to all mosquito control programs. In the absence of a dedicated disease surveillance program, mosquito control Operators should stay informed of arboviral occurrence or potential for occurrence in their control areas as determined by local, state, and/or national public health agencies.
Larval surveillance involves routine sampling of aquatic habitats for developing black flies. Larval surveillance is primarily accomplished by collecting stream substrates (rocks, vegetation, etc.) and examining for larval and pupal occurrence. Due to the varied developmental sites for black larvae and their ability to move in streams relative to changes in flow patterns, quantitative sampling will vary from site to site and in many instances, particularly with continuously changing water levels, is not practical. Qualitative sampling is often used in lieu of quantitative sampling, as an indicator of egg hatch and to indicate the age distribution of developing larvae. Qualitative sampling alone when used in conjunction with historical occurrence data can provide a reliable indicator of the need to initiate control activities.
Adult surveillance for black flies may include sweep sampling, vacuum aspiration of adults, and the use of silhouette traps. Traps may be simple visual attractants or may be baited with artificial attractants (e.g., ocentol and CO2). However, as different black fly species will respond differently in relation to different attractants, based on host preference, care must be used in selecting attractants that will provide a representative sample of the complete black fly spectrum present in any given location. Choice of adult sampling will in many cases be dictated by historical occurrence of black flies in a given area. Regardless, surveillance data is a useful tool in providing feedback to the mapping and planning component of any Pest Management Measure.
Aside from surveillance data, Decision-makers may also evaluate environmental conditions to assess the pest management area. For example, if the pest management area is known for pest development after flooding then Pest Management Measures may be needed after a rainstorm.
Reduce the impact on the environment and on non-target organisms by applying the pesticide only when the action threshold(s) has been met. Operators must apply pesticide only as indicated by action thresholds for the pest management area. As noted above, action thresholds, established by the Decision-maker, help determine both the need for control actions and the proper timing of such actions. Timing pesticide application can reduce the impact on the environment and on non-target organisms.
In situations or locations where practicable and feasible for efficacious control, use larvicides as a preferred pesticide for mosquito or flying insect pest control when the larval action threshold(s) has been met. Operators may use larvicides, adulticides or a combination of both. However, when practicable and feasible, larviciding should be the primary method for mosquito control. Larviciding is a general term for the process of killing mosquitoes by applying natural agents or manmade pesticide products designed to control larvae and pupae (collectively called larvicides) to aquatic habitats. Larviciding uses a variety of equipment, including aerial, from boats, and on the ground, as necessitated by the wide range of breeding habitats, target species, and budgetary constraints. Applications can be made using high pressure sprayers, ULV sprayers, handheld sprayers, and back sprayers. However, larviciding is only effective when a high percentage of the mosquito production sites are regularly treated, which may be difficult and expensive.
There are advantages and disadvantages to aerial and ground larvicide applications. Ground larviciding allows application to the actual treatment area and consequently to only those micro-habitats where larvae are present. Therefore, ground larviciding reduces unnecessary pesticide load on the environment. However, ground applications often rely on in-the-field human estimates of the size of treatment areas and equipment output with a greater chance of overdosing or under-dosing. Ground larviciding is also impractical for large or densely wooded areas and exposes Applicators to greater risk of insecticide exposure.
Aerial larviciding application methods are generally used for controlling mosquito larvae present in large areas and areas that are inaccessible for ground application. However, failure to treat an entire area with good larvicide coverage can result in the emergence of large adult populations. In order to prevent poor site coverage, a global positioning system (GPS), where economically feasible, or site flagging are necessary to increase accuracy of the pesticide application coverage while minimizing the amount of larvicides being applied. Aerial application does provide easier calibration of equipment due to the fact that the target area is generally mapped, and the material is weighed or measured when loading. However, cost of aerial application is higher than ground application (i.e. additional personnel for flagging or expensive electronic guidance systems) and also requires special FAA licenses, training of staff, and additional liability insurance. In addition, aerial larviciding has greater potential for non-target impacts.
Bacillus thuringiensis var israelensis (Bti) is the primary larvicide used for black fly control in the United States. Bti is a gram positive, aerobic, spore-forming bacterium that produces protoxins in the form of parasporal protein crystals. In the alkaline digestive tract of black flies and mosquitoes, the protoxins become activated into highly toxic delta-endotoxins. The endotoxins cause a rapid breakdown in the lining of the mid-gut and necrosis of skeletal muscles, resulting in paralysis and mortality of target insect pests. Bti is nontoxic to most non-target organisms due to their acidic digestive systems and lack of suitable tissue receptor sites.
To minimize pesticide discharges into waters of the United States, Operators must apply larvicides as needed for source reduction as indicated by the action threshold in situations or locations where it is practicable and feasible to do so. The action threshold may be based on occurrence of adults (current or historical) and/or larval sampling of stream substrates for immature black flies. Surveillance is also a valuable tool for assessing the effectiveness of larval control activities.
Larvicides may be applied to streams using either ground or aerial equipment. Choice of equipment is largely dictated by stream size and accessibility. Application equipment may include backpack sprayers, boats equipped with sprayers or metered release systems, helicopters or fixed wing aircraft. The amount of insecticide required to treat a stream should be based on the desired dosage and the stream discharge. Stream discharge is calculated by determining the average width and depth of the stream and the stream velocity (discharge = width (m) x depth (m) x velocity (m/s)). Proper calibration of insecticide delivery based on discharge is necessary to ensure complete coverage throughout the water column in order to expose all larval habitats to an effective insecticide dose.
A larvicide is applied across the stream width for the time specified by the application rate. The point of application should be far enough upstream from the larval habitat to ensure proper insecticide dispersal in the water passing over the treatment area. Operators should determine the effective downstream carry (maximum distance at which at least 80% larval control is achieved) of the insecticide suspension. By determining downstream carry, black fly control Operators can limit the number of applications necessary to treat any given stream and thereby reduce pesticide discharges into waters of the United States.
In situations or locations where larvicide use is not practicable or feasible for efficacious control, use adulticides for mosquito or flying insect pest control when the adult action threshold(s) has been met. Chemical pesticide applications for adult mosquitoes, adulticiding, is the most visible and commonly used form of mosquito control. Adulticide applications may be used for nuisance or disease vectoring mosquitoes. Adulticiding consists of dispersing an insecticide as a space spray into the air column, using ground or aerial equipment, which then remains suspended in the air column through the habitat where adult mosquitoes are flying. Any mosquito adulticiding activity that does not follow reasonable guidelines, including timing of applications, avoidance of sensitive areas, and strict adherence to the pesticide label, risks affecting non-target insect species.
Operators must ensure that the adulticide applications are made only when necessary by determining a need in accordance with specific criteria that demonstrate a potential for a mosquito-borne disease outbreak, or numbers of disease vector mosquitoes sufficient for disease transmission, or a quantifiable increase in numbers of pestiferous mosquitoes. To determine the need for adulticide application, at least one of the following criteria should be met and documented by records: 1) when a large population of adult mosquitoes is demonstrated by either a quantifiable increase in, or a sustained elevated mosquito population level as detected by standard surveillance methods, 2) where adult mosquito populations build to levels exceeding community standards (e.g., 25 mosquitoes per trap night or 5 mosquitoes per trap hour during crepuscular periods), and/or 3) when service requests for arthropod control from the public have been confirmed by one or more recognized surveillance methods.
The most common forms of adulticiding are ultra-low volume spray (ULV) and thermal fogging. Ground adulticiding is almost exclusively conducted with ULV equipment and is the most common method used to control mosquitoes. Ground adulticiding can be a very effective technique for controlling most mosquito species in residential areas with negligible non-target effects.
Aerial adulticiding is a very effective means of controlling adult mosquitoes, particularly in inaccessible areas, and may be the only means of covering a very large area quickly in case of severe mosquito outbreaks or vector borne disease epidemics. Aerial adulticide applications are made using either fixed wing aircraft or rotor craft. Application is generally as ULV spray, but some thermal fogging still occurs.
Adulticide application has its own set of conditions that determine success or failure. The application must be at a dosage rate that is lethal to the target insect and applied with the correct droplet size. Whether the pesticide application is ground or aerially applied, it must distribute sufficient insecticide to cover the prescribed area with an effective dose. Typically, with ground applications, vegetated habitats may require up to three times the dosage rates that open areas require. This is purely a function of wind movement and its ability to sufficiently carry droplets to penetrate foliage. In addition, aerial application is dependent upon favorable weather conditions.
Environmental conditions may also affect the results of adulticide application. Wind determines how the ULV droplets will be moved from the output into the treatment area. Conditions of no wind will result in the material not moving from the application point. High wind, a condition that inhibits mosquito activity, will quickly disperse the insecticide over too wide an area but at a diluted rate too low to effectively control pests. Light wind conditions (< 10 mph) are the most desirable because they move the material through the treatment area and are less inhibiting to mosquito activity. Thermal fogs perform best under very light wind conditions.
ULV application should be avoided during hot daylight hours. Thermal conditions, particularly temperature inversion, will cause the small droplets to quickly rise, moving them away from mosquito habitats. Generally, applications are made after sunset and before sunrise, depending upon mosquito species activity. Some mosquitoes (Culex and Anopheles) are most active several hours after sunset, while others (Ae. aegypti and Ae. albopictus) are more active during the daytime, and if these species are the targets, application should be made during the period of highest activity for the target species, provided that meteorological conditions are suitable for application (seldom during daylight hours).
One notable exception to applications made when mosquitoes are up and flying is a residual barrier treatment application. Barrier applications are based on the natural history and behavioral characteristics of the mosquito species causing the problem. Barrier applications use a residual material and are generally applied with a powered backpack sprayer to preferred resting areas and migratory stops in order to intercept adult mosquitoes hunting for blood meals. Barrier applications are often applied during daylight hours as a large-droplet liquid application and are designed to prevent a rapid re-infestation of specific areas, such as recreational areas, parks, special-event areas, and private residences. Barrier applications can help provide control of nuisance mosquitoes for up to one week or longer.
Pesticide control of black flies in the United States historically relied upon both larvicides and adulticides. However, adulticide use against black fly populations is no longer a common practice. As adult black flies are seeking blood meals during the daytime, adulticide application coincides with human activity, so daytime application is no longer a standard control procedure. One reason for this change is due to environmental factors associated with daytime adulticide application, particularly thermal inversions, which cause adulticide application for black fly control to be ineffective. Furthermore, as only adults directly contacted by the adulticide application are killed, with no residual activity against other adults immigrating to the treatment area, adulticide applications are both ineffective and expensive. For these reasons, larvicides which target the immature stages before development of the pestiferous adult are now the primary means of black fly control in the United States.
Recommended Mosquito Control References
EPA recommends the following sources for additional information on Pest Management Measures for mosquito control:
Anderson, RR and LC Harrington. 2010. Mosquito Biology for the Homeowner. Cornell Cooperative Extension  -  Medical Entomology Extension. Available at: http://blogs.cornell.edu/harrington/files/2014/01/Mosquito-Biology-for-the-Homeowner_final-2014-18iwdiw.pdf
American Mosquito Control Association. 2009. Mosquito Information. Available at: https://www.mosquito.org/page/mosquitoinfo?&hhsearchterms=%22mosquito+and+information%22
American Mosquito Control Association. 2009. Mosquito Info: Control. https://www.mosquito.org/page/control?&hhsearchterms=%22mosquito%22
California Department of Public Health. 2008. Best Management Practices for Mosquito Control on California State Properties. Available at: http://westnile.ca.gov/downloads.php?download_id=996&filename=CDPH_BMP_MosquitoControl6-08.pdf
Commonwealth of Massachusetts Department of Food and Agriculture State Reclamation and Mosquito Control Board. 1998. Generic Environmental Impact Report (GEIR)
For the Massachusetts Mosquito Control. Available at: http://www.mass.gov/eea/docs/agr/mosquitos/geir-docs/geir-full-text.pdf
Florida Coordinating Council on Mosquito Control. 2009. Florida Mosquito Control  -  The State of Mission as defined by mosquito controllers, regulators, and environmental managers. Available online at: http://mosquito.ifas.ufl.edu/Documents/Florida_Mosquito_Control_White_Paper.pdf
New York City Department of Health and Human Hygiene. 2016. Comprehensive Mosquito Surveillance and Control Plan. Available at: https://www1.nyc.gov/assets/doh/downloads/pdf/wnv/2016/wnvplan2016.pdf
Grodner, MG, J Criswell, C Sutherland, P Spradley, DL Renchie, ME Merchant, M Johnsen, and S Sawlis. 2007. The Best Way to Control Mosquitoes - Integrated Mosquito Management Explained. Available at: http://www.uaex.edu/publications/pdf/ag1166.pdf
Kwasny, DC, M Wolder, and CR Isola. 2004. Technical Guide to Best Management Practices for Mosquito Control in Managed Wetlands. Central Valley Joint Venture. Available at: http://www.centralvalleyjointventure.org/assets/pdf/CVJV-Mosquito-BMP.pdf
Rose, RI. 2001. Pesticides and Public Health: Integrated Methods of Mosquito Management. Emerging Infectious Diseases 7:1.
State of Massachusetts. 2008. Massachusetts Best Management Practices and Guidance for Freshwater Mosquito Control. Available at: http://www.mass.gov/eea/docs/agr/mosquitos/docs/mepa/document-2-freshwater-bmp-to-mepa-oct-24-2008.pdf
State of New Hampshire. 2008. Policy for Mosquito Control on State Lands. Available at: http://sos.nh.gov/ExecOrderLynch.aspx
State of New Mexico. 2008. Philosophy of Mosquito Control. http://nmhealth.org/publication/view/guide/992/
Washington State Department of Ecology/Water Quality Program. 2004. Best Management Practices for Mosquito Control. Available at: https://fortress.wa.gov/ecy/publications/publications/0310023.pdf
Recommended Black Fly Control References
EPA recommends the following sources for additional information on Pest Management Measures for black fly control:
Commonwealth of Pennsylvania. 2009. Black Fly Suppression Program. Available at: https://www.dep.pa.gov/Business/Water/CleanWater/BlackFly/Pages/default.aspx
Government of Alberta  -  Agriculture and Rural Development. 1993. Black Fly Control. Available at: https://open.alberta.ca/dataset/2397254#summary
Greater Los Angeles Vector Control District. 2008. Black Flies  -  Vector Services and Information. Available at: http://www.glacvcd.org/vector-information/black-flies/
Metropolitan Mosquito Control District. 2009. Biting Gnat Control. Available at: http://www.mmcd.org/biting-gnat-control/
North Carolina Cooperative Extension. 2005. Insect Notes  -  Black Flies and Their Control. Available at: http://www.ces.ncsu.edu/depts/ent/notes/Urban/blackfly.htm
North Elba  -  Black Fly Control Dept. 2009. About the black fly control program. Available at: http://www.northelba.org/?page=services/black-fly-control-dept
Ohio State University Extension. 1997. Factsheet  -  Black Flies. HYG-2167-97.
The Merck Veterinary Manual. 2016. Black Flies. Available at: http://www.merckvetmanual.com/mvm/integumentary_system/flies/black_flies.html?qt=black flies&alt=sh
Undeen, AH and DP Malloy. 1996. Use of stream width for determining the dosage rates of Bacillus Thuringiensis Var. israelensis for larval black fly (Diptera: Simuliidae) control. Journal of the American Mosquito Control Association. 12(2):312-315.
University of Florida. 2007. Featured Creatures  -  Black Flies. EENY-30. Available at http://entomology.ifas.ufl.edu/creatures/livestock/bfly.htm
University of New Hampshire Cooperative Extension. 2001. Black Flies. Available at: http://www.ultimate.com/washington/wla/blackfly/
2.2.2	Weed and Algae Pest Control
Part 2.2.2.a -- Identify the Problem
Prior to the first pesticide application covered under this permit that will result in a discharge to waters of the United States, and at least once each calendar year thereafter prior to the first pesticide application for that calendar year, any Decision-maker who is or will be required to submit NOI must do the following for each pest management area, as defined in Appendix A. Decision-makers must identify the pest problem in their pest management area prior to the first application covered under this permit. Knowledge of the pest problem is an important step to developing Pest Management Measures. Re-evaluation of the pest problem is also important to ensure Pest Management Measures are still applicable. Decision-makers must identify the pest problem at least once each calendar year prior to the first application for that calendar year.
Identify areas with pest problems and characterize the extent of the problems, including, for example, water use goals not attained (e.g. wildlife habitat, fisheries, vegetation, and recreation). Decision-makers must be well-acquainted with the unique regional conditions of their sites and available Pest Management Measures for controlling the pest present. Intended use goals for the water bodies that are being impeded because of nuisance pest infestation must also be considered based on the control site. The use of the best available mapping information to aid in identifying the problem areas is suggested. Mapping may include aerial photo assessments, topographic maps, and satellite imagery, where available and/or practicable. Mapping can be essential to identify problem areas which can and cannot be controlled using non-pesticide preventative measures (e.g., mechanical control). Mapping can also be used in plotting the regional target pest, as well as water use goals and complaints or reports of weeds and algae from the public.
Identify target pest(s). Positive identification of the pest is required because many pests within the same genera may require different levels and types of Pest Management Measures. Pest identification is important when determining the best Pest Management Measures for each pest and for determining application areas. Decision-makers should develop Pest Management Measures based on identification of the targeted pest which occur in their area.
Identify possible factors causing or contributing to the pest problem (e.g., nutrients, invasive species, etc.). While there may not be reasonable means to control and/or stop the introduction and occurrence of some nuisance pest infestations, the identification of possible sources (e.g., outflows from other water systems/bodies) may help in reducing the need for pesticide. Potential weed and algae causes, such as changes in nutrient levels or accidental or intentional introduction of exotic species, must be identified.
Establish any pest- and site-specific action threshold, as defined in Appendix A, for implementing Part 2.2.2b. Any data and/or information regarding pest can be used to establish an action threshold. An action threshold must be established.
In the event there are no data for the pest management area in the past calendar year, use other available data as appropriate to meet the permit conditions in Part 2.2.2.a. Decision-makers may use historical data or neighboring district data to identify the pest and establish action thresholds.
Part 2.2.2.b -- Pest Management Options
Prior to the first pesticide application covered under this permit that will result in a discharge to waters of the United States, and at least once each calendar year thereafter prior to the first pesticide application for that calendar year, any Decision-maker who is or will be required to submit an NOI must select and implement efficient and effective means of Pest Management Measures that minimize discharges resulting from the application of pesticides to control pests. In developing the Pest Management Measures for each pest management area, the Decision-makers must evaluate the following management options, including a combination of these management options, considering impact to water quality, impact to non-target organisms, feasibility, and cost effectiveness: No action; Prevention; Mechanical/physical methods; Cultural methods; Biological control agents; and Pesticides. Decision-makers must evaluate management options and implement Pest Management Measures to minimize pesticide discharges into waters of the United States prior to the first pesticide application covered under this permit. As noted above, combinations of various management options are frequently the most effective Pest Management Measures over the long term. The goal should be to emphasize long-term control rather than a temporary fix. Decision-makers must reevaluate every year prior to the first pesticide application for that calendar year. All Pest Management Measures must be implemented in a manner that reduces impacts to non-target species. The following describes the management options that must be evaluated.
No Action
No action is to be taken, although pest problem has been identified. This may be appropriate in cases where, for example, available pest management options may cause secondary or non-target impacts that are not justified, no available controls exist, or the pest population is stable at a level that does not impair water body uses.
Prevention
Preventing introductions of possible pest is the most efficient way to reduce the threat of nuisance species (ANS TaskForce, http://www.anstaskforce.gov/default.php). Identifying primary pathways of introduction and actions to cut off those pathways is essential to prevention. Through a better understanding of the transportation and introduction of pest, private entities (aquaculture) and the public have the necessary knowledge to assist in local pest control by reducing conditions that encourage the spread of pests in their immediate surroundings. For example, recreational water users provide a pathway of unintentional introductions. Increasing public awareness of weeds and algae, their impacts, and what individuals can do to prevent their introduction and spread is critical for prevention. Other examples of prevention include: better design of water holding sites, better management and maintenance of potential problem sites, and volunteer removal of pest (e.g., hand weeding). Monitoring and detection also play important roles in the prevention of the spread and introduction of weeds and algae.
Mechanical or Physical Methods
Mechanical control techniques will vary depending on the pest. Examples include dewatering, pressure washing, abrasive scrubbing, and weed removal by hand or machine. Mechanical and biological controls will be the appropriate method in some cases, or a part of a combination of methods. In some instances, the need for chemical pesticide use in and adjacent to the affected habitat can be reduced or virtually eliminated with proper execution of Pest Management Measures.
Cultural Methods
Cultural techniques include the use of pond dyes and water-level drawdown. The use of certain pond dyes may help manage filamentous algae and submersed (underwater) vegetation. Several pond colorants and one or two dyes are EPA-registered for weed control. Pond dyes and colorants can be effective if there is little water outflow from the pond. Dyes and colorants intercept sunlight needed by algae and other underwater plants for photosynthesis. Therefore, they are generally ineffective on floating plants like duckweed and water lilies and emergent (growing above the surface) plants like cattails and bulrushes. Dyes and colorants are nontoxic and do not kill the plants, and they are safe for use in ponds for irrigation, fishing, and livestock. However, they are not intended for use in large lakes with a lot of water flow or lakes used for public water supplies.
Biological Control Agents
Biological control of weeds and algae may be achieved through the introduction of diseases, predators, or parasites. While biological controls generally have limited application for control of weeds and algae, the Operator should fully consider this option in evaluating pest management options.
Pesticides
Aquatic herbicides are chemicals specifically formulated for use in water to kill or control aquatic plants. Aquatic herbicides are sprayed directly onto floating or emergent aquatic plants as well as plants at or near the water's edge or are applied to the water in either a liquid or pellet form. Systemic herbicides are capable of killing the entire plant. Contact herbicides cause the parts of the plant in contact with the herbicide to die back, leaving the roots alive and able to regrow. Non-selective, broad spectrum herbicides will generally affect all plants that they come in contact with. Selective herbicides will affect only some plants.
Part 2.2.2.c. -- Pesticide Use
Conduct surveillance in an area that is representative of the pest problem prior to each pesticide application to assess the pest management area and to determine when the action threshold(s) is met. Often, each weed and algae and pest management area warrant different Pest Management Measures tailored to regional conditions. The Pest Management Measures should consist of combinations of mechanical, biological, and/or pesticidal control methods. All Pest Management Measures must be conducted in a manner that minimizes impacts to non-target species.
Decision-makers should apply chemical pesticides only after considering the alternatives and determining those alternatives not to be appropriate Pest Management Measures. Also, Decision-makers should conduct surveillance (e.g., pest counts or area survey) prior to application of pesticides to determine when the action threshold is met thus necessitating the need for implementing Pest Management Measures.
Surveillance may include the relatively sophisticated transect method used in ecological studies to evaluate species distribution, or it may consist of simply conducting visual observations in the treated area to verify the eradication or reduction in populations of weeds and algae following pesticide application (Getsinger et al. 2005, pp 23-25).
Reduce the impact on the environment and non-target organisms by applying the pesticide only when the action threshold has been met. Operators must apply pesticide only as indicated by action thresholds for the pest management area. As noted above, action thresholds help determine both the need to implement Pest Management Measures and the proper timing of such actions. Timing pesticide application can reduce the impact on the environment and on non-target organisms.
Environmental factors such as temperature and dissolved oxygen content, as well as biological factors such as stage of growth, should be considered when deciding on application timing. Partial site pesticide applications over time may be considered to reduce risk. Pesticide application must be limited to the appropriate amount required to control the target pests. Methods used in applying pesticides must reduce the impact to non-target species.
Recommended Weed and Algae Control References
EPA recommends the following sources for additional information on Pest Management Measures for weed and algae control:
Aquatic Nuisance Species Taskforce. Available at http://www.anstaskforce.gov/default.php.
Getsinger, K., Moore, M. D., Layne, C. P., Petty, D. G., L, S., Sprecher, Dibble, E. D., Karcas, E., Maceina, M., Mudrak, V., Lembi, C., Madsen, J. D., Stewart, R. M., Anderson, L., Haller, W., Confrancesco, A., Newman, R., & Nibling, F. (2005). Aquatic Plant Management Best Management Practices in Support of Fish and Wildlife Habitat. Aquatic Ecosystem Restoration Foundation. Lansing, MI.
Gettys, L. A., Haller, W. T., & Bellaud, M. (2009). Biology and control of aquatic plants. Marietta GA: Aquatic Ecosystem Restoration Foundation. Available at http://www.fs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb5373509.pdf
2.2.3	Animal Pest Control
Part 2.2.3.a -- Identify the Problem
Prior to the first pesticide application covered under this permit that will result in a discharge to waters of the United States, and at least once each calendar year thereafter prior to the first pesticide application for that calendar year, any Decision-maker who is or will be required to submit an NOI must do the following for each pest management area, as defined in Appendix A. Decision-makers must identify the pest problem in their pest management area prior to the first application covered under this permit. Knowledge of the pest problem is an important step to developing Pest Management Measures. Re-evaluation of the pest problem is also important to ensure Pest Management Measures are still applicable. Decision-makers must identify the pest problem at least once each calendar year prior to the first application for that calendar year.
Identify areas with pest problems and characterize the extent of the problems, including, for example, water use goals not attained (e.g. wildlife habitat, fisheries, vegetation, and recreation). Decision-makers must be well-acquainted with the unique regional conditions of their sites and available Pest Management Measures for controlling the pest present. Intended use goals for the water bodies that are being impeded because of nuisance pest infestation must also be considered based on the control site.
The use of the best available mapping information to aid in identifying the problem areas is suggested. Mapping may include aerial photo assessments, topographic maps, and satellite imagery where available and/or practicable. Mapping can be essential to identify problem areas which can and cannot be controlled using non-pesticide preventative measures (e.g., mechanical control). Mapping can also be used in plotting the regional distribution of desired aquatic species, as well as water use goals and complaints or reports of pests from the public.
Identify target pest(s). Positive identification of the pest is required because many pests within the same genus may require different levels and types of Pest Management Measures. Animal identification is important when determining the best Pest Management Measures for each particular pest and for determining application areas. Decision-makers must develop Pest Management Measures based on identification of the targeted pest which occur in their area.
Identify possible factors causing or contributing to the problem (e.g., nutrients, invasive species). While there may not be reasonable means to control and/or stop the introduction and occurrence of some pest infestations, the identification of possible sources (e.g., outflows from other water systems/bodies) may help in minimizing the need for implementing Pest Management Measures. Potential factors which could lead to the establishment of animal populations such as accidental or intentional introduction of exotic species must be identified before Pest Management Measures are implemented.
Establish any pest- and site-specific action threshold, as defined in Appendix A, for implementing Part 2.2.3.b. An action threshold should be established before implementing Pest Management Measures. Any data and/or information regarding pest can serve as an action threshold.
In the event there are no data for the pest management area in the past calendar year, use other available data as appropriate to meet the permit conditions in Part 2.2.3.a. Decision-makers may use historical data or neighboring district data to identify the pest and establish action thresholds.
Part 2.2.3.b -- Pest Management Options
Prior to the first pesticide application covered under this permit that will result in a discharge to waters of the United States, and at least once each year thereafter prior to the first pesticide application during that calendar year, any Decision-maker who is or will be required to submit an NOI must select and implement efficient and effective means of Pest Management Measures that minimize discharges resulting from the application of pesticides to control pests. In developing the Pest Management Measures for each pest management area, the Decision-maker must evaluate the following management options, including a combination of management options, considering impact to water quality, impact to non-target organisms, feasibility, and cost effectiveness: No action; Prevention; Mechanical/physical methods; Biological control agents; and Pesticides. Decision-makers are required to evaluate management options and implement Pest Management Measures to minimize pesticide discharges into waters of the United States prior to the first pesticide application covered under this permit. As noted above, combinations of various management options are frequently the most effective Pest Management Measures over the long term. The goal should be to emphasize long-term control rather than a temporary fix. Decision-makers must reevaluate every year prior to the first pesticide application for that calendar year. All Pest Management Measures must be conducted in a manner that minimizes impacts to non-target species. The following describes the management options that must be evaluated.
No Action
No action is to be taken, although an animal pest problem has been identified. This may be appropriate in cases where, for example, available control methods may cause secondary or non-target impacts that are not justified, or no available controls exist.
Prevention
Preventing introductions of possible nuisance species is the most efficient way to reduce the threat of aquatic nuisance animals (ANS Task Force, 2009). Identifying primary pathways of introduction and actions to cut off those pathways is essential to prevention. Through a better understanding of the transportation and introduction of animals, private entities (aquaculturists) and the public have the necessary knowledge to assist in local animal control by reducing conditions that encourage the spread of animals in their immediate surroundings. For example, recreational water users provide a pathway of unintentional introductions. Increasing public awareness of pests, their impacts, and what individuals can do to prevent their introduction and spread is critical for prevention. Other examples of prevention include, better design of water holding sites, better management and maintenance of potential problem sites, and volunteer removal of pest species (e.g., fishing). Monitoring and detection also play important roles in the prevention of the spread and introduction of pests.
Mechanical or Physical Methods
Mechanical and biological controls will be the appropriate methods in some cases of pest control, or a part of a combination of methods. Mechanical control techniques will vary depending on the pest. Examples include fishing, dewatering, netting, electrofishing, pressure washing, use of electric fences, and abrasive scrubbing.
Biological Control Agents
Biological control of animals may be achieved through the introduction of diseases, predators, or parasites. While biological control generally has limited application for control of animals, Decision-makers should fully consider this option.
Pesticides
Chemical and biological pesticides such as lampricides, molluscides, insecticides, and piscicides, are registered for use to control animal pests. These pesticides are specifically formulated for use in water where aquatic nuisance animals occur. In some cases, pesticide use may impact non-target species. As described below, once the determination is made to use pesticides, additional requirements must be met.
Part 2.2.3.c. -- Pesticide Use
Conduct surveillance in an area that is representative of the pest problem prior to each application to assess the pest management area and to determine when the action threshold(s) is met. Often, each animal and pest management area warrant different Pest Management Measures, tailored to the regional conditions. Pest Management Measures should consist of combinations of mechanical, biological, and/or pesticidal control methods. All Pest Management Measures must be conducted in a manner that minimizes impacts to non-target species.
Operators must apply chemical pesticides only after considering the alternatives and determining those alternatives not to be appropriate Pest Management Measures. In some instances, the need for chemical pesticide use in and adjacent to the affected habitat can be reduced or virtually eliminated with proper execution of alternative strategies and best management practices. If pesticides are used, they must only be used as needed as determined by an action threshold, and Pest Management Measures must be implemented, including use of the minimum effective application rate. Also, the Decision-maker must conduct surveillance (e.g., pest counts or area survey) prior to application of pesticides to determine when the action threshold is met that necessitates the need for implementing Pest Management Measures.
Surveillance may include the relatively sophisticated transect method used in ecological studies to evaluate species distribution, or it may consist of simply conducting visual observations in the treated area to verify the eradication or reduction in populations of aquatic nuisance animals following pesticide application (Getsinger et al. 2005, pp 23-25).
Reduce the impact on the environment and non-target organisms by evaluating site restrictions, application timing, and application method in addition to applying the pesticide only when the action threshold(s) has been met. The pest and site restrictions (water use, water movement, etc.) must be identified when choosing an appropriate pesticide. Environmental factors such as temperature as well as biological factors such as migration timing should be considered when deciding on application timing. Partial site pesticide applications over time may be considered to minimize risk to non-target organisms.
Pesticide application must be limited to the appropriate amount required to control the target pests. Methods used in applying pesticides must minimize the impact to non-target species. For piscicides, chemical deactivation is currently required for all lotic (flowing water) environments. Management agencies typically work downstream throughout the watershed in consecutive treatments as this will require the least amount of chemical deactivation. Most invertebrates repopulate treated areas through immigration (typically in the direction of flow); as such headwater streams/tributaries seem to be effective at accomplishing this. EPA also notes that not all piscicides are that harmful to invertebrate populations (e.g., antimycin is more selective for scaled fish). It can be difficult to know the point at which headwater streams are "fishless"; however, most fishery management agencies do not treat streams unless they are considered a refuge for target species.
Recommended Animal Pest Control References
EPA recommends the following sources for additional information on Pest Management Measures for animal control:
Aquatic Nuisance Species Taskforce. Online: http://www.anstaskforce.gov/.
Getsinger, K., Moore, M. D., Layne, C. P., Petty, D. G., L, S., Sprecher, Dibble, E. D., Karcas, E., Maceina, M., Mudrak, V., Lembi, C., Madsen, J. D., Stewart, R. M., Anderson, L., Haller, W., Confrancesco, A., Newman, R., & Nibling, F. (2005). Aquatic Plant Management Best Management Practices in Support of Fish and Wildlife Habitat. Aquatic Ecosystem Restoration Foundation. Lansing, MI.
2.2.4	Forest Canopy Pest Control
Part 2.2.4.a -- Identify the Problem
Prior to the first pesticide application covered under this permit that will result in a discharge to waters of the United States, and at least once each calendar year thereafter prior to the first pesticide application in that calendar year, any Decision-maker who is or will be required to submit an NOI must do the following for each pest management area, as defined in Appendix A. In order to reduce pesticide discharges into waters of the United States associated with forest canopy pest control, it is important for Decision-makers to ensure proper problem identification. Problem identification is determined through pest identification, delineation of the extent and range of the pest problem, determination of the potential for pest problem expansion, and assessing the economic impact of not implementing Pest Management Measures.

Establish any pest- and site-specific action threshold, as defined in Appendix A, for implementing Part 2.2.4.b. Decision-makers must develop action thresholds for the target pests prior to the first pesticide application as covered under the draft 2021 PGP. The action thresholds must be re-evaluated at least once each calendar year. As noted in the general discussion above, an action threshold is a point at which pest populations or environmental conditions indicate that Pest Management Measures must be taken. Action thresholds help determine both the need for implementing Pest Management Measures and the proper timing of such actions. It is a predetermined pest level that is deemed to be unacceptable.
Identify target pest(s) to develop Pest Management Measures based on developmental and behavioral considerations for each pest. Pest identification is a key activity for implementation of a forest canopy pest control system. Pest identification should only be conducted by personnel with adequate training and experience with the pests. While numerous similar pests (insects and/or pathogens) may be present in any given location, only a few of the representative pest may constitute a threat which requires control activities. Through proper pest identification informed control decisions can be made based on the development biology of the pest (susceptible development stage), pest mobility (potential rate of spread), timing of selected Pest Management Measures, applicable control techniques, and most effective chemical pesticides for the target pests (insecticide class, resistance, etc.). Failure to identify pests can lead to unwarranted control activities and/or the need for chemical application with potential for discharges of pollutants into waters of the United States. Control for each specific pest is also predicated on the status of the pest as native recurring, quarantine restricted, or designated as an invasive species.
Identify current distribution of the target pest and assess potential distribution in the absence of Pest Management Measures. Control activities are warranted only after exact pest identification and delineation of the extent of the pest infestation. As forest canopy pest control can involve treating large expanses of forests, mapping is also an important component in identification of the problem. The distribution of the pest, usually insects, within the area of infestation can impact the selection of Pest Management Measures. In addition, mapping of the pest infestation will allow evaluation of the actual/potential spread of the infestation (e.g., pest biology, pest mobility, and host availability) and also serve as a tool to evaluate the effectiveness of the Pest Management Measures. Mapping can also provide essential information for assessment of economic damages that can result from the current and potential pest infestation and failure to control the pest. Management decisions can thereby be based on cost/benefit evaluations based on the current and potential distribution of any pest.
The third component of problem identification is to determine the potential economic impact of not controlling the pest. By establishing economic thresholds, it is possible to determine pest action thresholds which warrant control activities. However, control decisions must take into account not only the projected economic impact of the current pest infestation but also the potential of the pest infestation to spread. Therefore, control decisions based on economic impact must in turn rely on proper pest identification, pest biology, and current and potential pest distribution.
In the event there are no data for the pest management area in the past calendar year, use other available data as appropriate to meet the permit conditions in Part 2.2.4.a. Decision-makers may use historical data or neighboring district data to identify the pest and establish action thresholds.
Part 2.2.4.b. -- Pest Management Options
Prior to the first pesticide application covered under this permit that will result in a discharge to waters of the United States, and at least once each calendar year thereafter prior to the first pesticide application for that calendar year, any Decision-maker who is or will be required to submit an NOI must select and implement efficient and effective means of Pest Management Measures that minimize discharges resulting from the application of pesticides to control pests. In developing the Pest Management Measures for each management area, the Decision-maker must evaluate the following management options, including a combination of management options, considering impact to water quality, impact to non-target organisms, feasibility, and cost effectiveness: No action; Prevention; Mechanical/physical methods; Cultural methods; Biological control agents; and Pesticides. Pest control activities in forest canopy management programs may be warranted following problem identification and based solely on pest occurrence (e.g., quarantine pest, invasive species). However, in many instances control activities may only be necessary based on pest population distribution and/or pest densities. To minimize the need for pest control while also producing the best control results, Pest Management Measures appropriate for the specific problem site(s) must be developed. A site-specific management plan will consider biotic (e.g., plant and animal species community structure) and abiotic (e.g., environmental) factors. Combinations of various management options are frequently the most effective Pest Management Measures over the long term. The goal of Pest Management Measures in forest canopy pest control should be to emphasize long-term control rather than a temporary fix.
All Pest Management Measures must be conducted in a manner that minimizes impacts to non-target species. The following is a discussion of the relevant management options as they might be implemented for forest canopy pest control.
No Action
No action is to be taken, although a pest problem has been identified. This may be appropriate in cases where available control methods may cause secondary or non-target impacts or where aesthetic/economic losses are not anticipated.
Mechanical/Physical Methods
Mechanical and biological controls will be the appropriate method in some cases, or a part of a combination of methods. In some instances, the need for chemical pesticide use in and adjacent to the affected habitat can be reduced or virtually eliminated with proper execution of alternative measures and best management practices.
Mechanical control techniques will vary depending on the pest. An example of mechanical control in a forest canopy would be egg mass removal (e.g., gypsy moth).
Cultural Methods
Cultural control methods are Pest Management Measures that make the habitat unsuitable for a pest. An example of a cultural method to manage pests of the forest canopy would be to select a different species of tree to plant, or to plant resistant varieties of trees. Maintaining the trees in good health to discourage pests is another method of cultural control.
Biological Control Agents
Biological control of forest canopy pests may be achieved through the introduction/enhancement of diseases, predators, or parasites. In addition, forest canopy pest control programs aimed specifically at insects may also utilize sterile insect release, mating disruption, and biological pesticides. While biological controls generally have limited applications for forest canopy pest control programs, they should be fully considered as an option in the development of Pest Management Measures. The latter two control approaches are often utilized when controlling for gypsy moth.
Pesticides
Several chemical and biological pesticides are available that may be used to reduce defoliation of the trees. These pesticides are typically used when pest populations are high, and the action threshold has been reached. They are aerially applied. As described below, once the determination is made to use pesticides, additional requirements must be met.
Part 2.2.4.c. -- Pesticide Use
Conduct surveillance in an area that is representative of the pest problem prior to each application to assess the pest management area and to determine when the pest action threshold is met. Decision-makers must apply pesticides only as needed as determined by pre-established criteria and pest action thresholds. Decision-makers must establish a pest action threshold that warrants pesticide application based on problem identification and pest surveillance. In order to establish pest densities and determine when pest action thresholds have been met, forest canopy pest control programs must include pest surveillance activities as an integral component of Pest Management Measures. Pest surveillance is necessary to detect the presence (or confirm the absence) and magnitude of pest populations in a given location and precisely pinpoint zones of infestation. Surveillance activities will vary according to the pest (insect, weed, or pathogen) but in general should include observations of pest numbers, developmental stage of the current infestation, and biotic factors which would enhance development/expansion of pest populations (e.g., weather, crowding, predators, pathogens, etc.).
Pest surveillance will vary according to pest type and species. For insect pests, surveillance activities may include, but not be limited to, pheromone traps, sticky traps, light traps, defoliation monitoring. In some cases, traps used in surveillance activities have been developed to the extent that they alone provide adequate control of the targeted pest, thus eliminating the need for pesticides completely. Conversely, in the instance of quarantine pests or invasive species, pest identification alone may suffice to fulfill surveillance requirements and indicate need for control measures. Regardless, surveillance should take into account local environmental conditions and projected environmental conditions, which would support development and/or spread of the pest population and which would limit the choice or effectiveness of control activities.
It is also important to continue surveillance following control activities to assess the efficacy of Pest Management Measures and to monitor for new pests. Surveillance can determine if the current techniques are effective and whether additional Pest Management Measures are required, particularly pesticide application. Based on follow-up surveillance activity, Decision-makers can make informed decisions which serve to increase the effectiveness of their control programs and minimize the potential for pollutant discharges to waters of the United States. Surveillance is necessary not only to establish the pest presence and its abundance but also as an evaluation tool of the effectiveness of chemical control activities. Furthermore, surveillance should be used as an indicator of the need for additional chemical control activities based on pre-established criteria related to population densities in local areas.
Reduce the impact on the environment and non-target organisms by evaluating the restrictions, application timing, and application methods in addition to applying the pesticide only when the action threshold(s) have been met. Forest canopy pest and site restrictions (water use, water movement, etc.) must be identified when choosing an appropriate pesticide. For instance, with gypsy moth control, a biological insecticide, Bacillus thuringiensis kurstaki, is usually selected. However, if endangered or threatened butterfly or moth species are in the area, a viral insecticide that specifically targets gypsy moth larvae should be considered. Environmental factors such as temperature, as well as biological factors such as migration timing, should be considered when deciding on application timing. Partial site pesticide applications over time may be considered to minimize risk to non-target organisms. Pesticide application must be limited to the appropriate amount required to control the target pests. Methods used in applying pesticides should weigh the potential impact to non-target species.
Evaluate using pesticides against the most susceptible developmental stage. For forest canopy pests, pesticides should be selected that target the most susceptible life stage. Gypsy moth caterpillars are susceptible to control by chemical pesticides, or by ingestion of nucleopolyhedrosis virus occlusion bodies.
Recommended Forest Canopy Pest Control Reference
EPA recommends the following sources for additional information on Pest Management Measures for forest canopy pest control:
Emily Grafton and Ralph Webb. Homeowner's guide to gypsy moth management. West Virginia University Extension Service. http://www.nj.gov/agriculture/divisions/pi/pdf/GMguide.pdf
USDA. (rev. 2019). Gypsy Moth Program Manual. http://www.aphis.usda.gov/import_export/plants/manuals/domestic/downloads/gypsy_moth.pdf
USDA. 2016. Asian Gypsy Moth Factsheet. http://www.aphis.usda.gov/publications/plant_health/content/printable_version/fs_phasiangm.pdf
Reardon, Podgwaite, and Zerillo. GYPCHEK- Environmentally Safe Viral Insecticide for Gypsy Moth. FHTET-2012-01. 2[nd] ed. March 2016. U.S. Department of Agriculture, Forest Service. http://www.fs.fed.us/foresthealth/technology/pdfs/Gypchek_FHTET-2012-01_2ndEd.pdf
Kucera, Daniel and P. Orr. Spruce Budworm in the Eastern United States. U.S. Department of Agriculture, Forest Service. Forest Insect and Disease Leaflet 160. https://www.fs.usda.gov/Internet/FSE_DOCUMENTS/fsbdev2_042853.pdf
Michael, Jerry. 2004. Best Management Practices for Silvicultural Chemicals and the Science behind Them. Water, Air, and Pollution: Focus. 4(1), 95-11
Water Quality-Based Effluent Limitations
In addition to technology-based effluent limitations for all discharges of pollutants, the CWA requires additional effluent limitations that are as stringent as necessary to achieve water quality standards. These are called water quality-based effluent limitations (WQBELs). Permit writers are to assess whether the technology-based effluent limitations are protective of water quality standards, and if not, permit writers must also include WQBELs as necessary to ensure that the discharge of pollutants will not cause an excursion above any state water quality standard, including state narrative criteria for water quality (see 40 CFR 122.44(d)). In developing WQBELs, permit writers must consider the potential impact of every proposed surface water discharge of pollutants on the quality of the receiving water. Unlike individual permits that include requirements tailored to site-specific considerations, general permits, while tailored to specific industrial processes or types of discharges of pollutants (e.g., from the application of pesticides), often do not contain site-specific WQBELs. Instead, in general, EPA includes a narrative statement that addresses WQBELs. In this permit the WQBEL is as follows:
All Operators must control discharges as necessary to meet applicable numeric and narrative state, territory, or tribal water quality standards, for any discharges authorized under this permit, with compliance required upon beginning such discharge.
If at any time an Operator becomes aware (e.g., through self-monitoring or by notification from the state, tribe, or territory), or EPA determines, that a discharge causes or contributes to an excursion of any applicable water quality standards, the Operator must take corrective action as required in Part 6 up to and including the ceasing of the discharge, if necessary.
The first sentence includes the general requirement to control discharges of pollutants as necessary to meet water quality standards, while the second sentence implements this requirement in more specific terms by imposing on Operators a responsibility to take corrective action in response to an excursion of applicable water quality standards, whether discovered by EPA or by the Operator. Failure to take such corrective action is a violation of the permit. Additionally, the permit includes a provision, in Part 1.2.3 of the draft 2021 PGP, that specifies that EPA may determine that additional technology-based and/or water quality-based effluent limitations are necessary, or may deny coverage under this permit and require submission of an application for an individual NPDES permit, as detailed in Part 1.3.
Each Operator is required to control its discharge of pollutants as necessary to meet applicable water quality standards. In general, EPA expects that compliance with the other conditions in this permit (e.g., the technology-based limitations, corrective actions, etc.) will result in discharges of pollutants that are controlled as necessary to meet applicable water quality standards based on the cumulative effect of the following factors, which are described below:
     (1) Under FIFRA, EPA evaluates risk associated with pesticides and mitigates unreasonable ecological risk. Compliance with FIFRA is required. (See Part III.1.5 of the fact sheet.)
(2) In developing the PGP, EPA evaluated national - scale ambient monitoring data, as well as the frequency of the identification of specific pesticides as the cause of water impairments, to assess whether pesticide residues are currently present in waters at levels that would exceed water quality standards. The monitoring data, although limited in scope, show that, in most samples, most pesticides were below ambient water quality criteria or benchmarks developed by EPA's Office of Pesticide Programs (OPP). For the assessment of the USGS National Water-Quality Assessment Program's 1992-2001 data, ambient water quality criteria were available for 7 of the 83 analytes and one or more OPP benchmarks were available for 60 of the 83 analytes. For the small number of pesticides found in monitoring data to be present above such benchmarks, the evaluation, as summarized in Appendices B and C of the fact sheet for the 2011 PGP, also documents risk mitigation actions taken by EPA (such as cancellation of pesticide uses) that EPA expects have reduced the levels of those pesticides in water EPA also assessed the study USGS National Water-Quality Assessment Program (NAWQA) released in 2014. A summary of the evaluation and risk mitigation actions taken by EPA is available in Appendices B and C of the fact sheet for this permit.
     (3) Technology-based effluent limitations in the draft 2021 PGP provide further protections beyond compliance with existing FIFRA requirements.
     (4) Biological pesticides discharged to waters, by regulatory definition, do not work through a toxic mode of action. For chemical pesticides, the discharges of pollutants covered under the draft 2021 PGP are the residues after the pesticide has performed its intended purpose. Thus, the residue will be no higher than, and in many instances, lower than, the concentration of the pesticide as applied.
     (5) The draft 2021 PGP excludes pesticide applications that result in discharges of any pollutant to (1) waters impaired for an active ingredient of that pesticide or a degradate of such an active ingredient, or (2) any Tier 3 waters (i.e., outstanding national resource waters) except for pesticide applications made to restore or maintain water quality or to protect public health or the environment that either do not degrade water quality or only degrade water quality on a short-term or temporary basis.
     (6)	EPA has no evidence in the record that implementation of the 2011 and 2016 PGP has resulted in documented water quality problems.
In addition to the six factors identified above, EPA cannot issue an NPDES permit until the state, territory or tribe in which the discharge originates certifies that the discharge will comply with applicable provisions of the CWA or waives certification. Therefore, Part 9 of the final 2021 PGP will include conditions included by States, and authorized Tribes in their CWA § 401 certification actions on the 2021 PGP, which meet the requirements of CWA Section 401 and EPA's CWA Section 401 implementing regulations. 40 C.F.R. § 124.53(e)(1).
This draft 2021 PGP requires Operators to control discharges of pollutants as necessary to meet applicable water quality standards. When the Operator or EPA determines a discharge of pollutants will cause or contribute to an excursion above any WQS, including failure to protect and maintain existing designated uses of receiving waters, the Operator must take corrective action to ensure that the situation is eliminated and will not be repeated in the future. (See Part 6.0 of the draft 2021 PGP). If additional Pest Management Measures are required, the Operator is required to follow and document, as applicable, the process for Pest Management Measure selection, installation, implementation and maintenance, and cooperate to eliminate the identified problem within the timeframe stipulated in Part 6.0 of the draft 2021 PGP.
(1) Under FIFRA, EPA evaluates risks associated with pesticides and considers mitigation measures to address risks that exceed levels of concern.
Background