1 of 94 UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D. C. 20460 OFFICE OF PREVENTION, PESTICIDES AND TOXIC SUBSTANCES MEMORANDUM Date: September 13, 2005 Subject: Dicamba. Residue Chemistry Considerations for the Reregistration Eligibility Decision ( RED) Document. Summary of Analytical Chemistry and Residue Data.

DP Number: D317703 Decision Number: 357484 Chemical Class: Benzoic acid herbicide 40 CFR § 180: 227 PC Codes: 029801  Dicamba acid 029802  Dimethylamine ( DMA) salt of dicamba 029806  Sodium ( Na) salt of dicamba 128931  Diglycolamine ( DGA) salt of dicamba 128944  Isopropylamine ( IPA) salt of dicamba 129043  Potassium ( K) salt of dicamba From: Christine L, Olinger, Chemist Reregistration Branch I Health Effects Division ( 7509C)

Through: Whang Phang, Ph. D., Branch Senior Scientist Reregistration Branch I Health Effects Division ( 7509C)

Chemistry Science Advisory Council Health Effects Division ( 7509C)

To: Kendra Tyler, CRM Reregistration Branch 1 Special Review and Reregistration Division ( 7508C)

This document was originally prepared under contract by Dynamac Corporation ( 20440 Century Boulevard, Suite 100; Germantown, MD 20874; submitted 06/ 16/ 2005). The document has been reviewed by the Health Effects Division ( HED) and revised to reflect current Office of Pesticide Programs ( OPP) policies. Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 2 of 94 Executive Summary Dicamba ( 3,6 dichloro 2 methoxybenzoic acid is a selective benzoic acid herbicide registered for the control of weeds prior or before their emergence. Different forms of dicamba ( acid and salt) have registered uses on several food/ feed crops including asparagus, barley, corn ( field and pop), grasses grown in pasture and rangeland, oats, proso millet, rye, sorghum, soybeans, sugarcane, and wheat. Application rates range from 0.5 to 2.8 lb ae/ A.

The Agency's Special Review and Reregistration Division ( SRRD) issued a Use Closure Memorandum for Dicamba ( Case No. 0065) on 8/ 2/ 05 in an attempt to provide use information that will be incorporated into the preliminary risk assessment for dicamba. The registrants intend to support all currently registered uses described in the Use Closure Memo and all currently registered products. The different forms of dicamba acid and salts that will be supported for reregistration, include: the dicamba acid ( PC Code 029801), dimethylamine ( DMA) salt ( PC Code 029802), sodium ( Na) salt ( PC Code 029806), isopropylamine ( IPA) salt ( PC Code 128944), diglycolamine ( DGA) salt ( PC Code 128931), and potassium ( K) salt ( PC Code 129043).

The nature of the residue in plants is adequately understood based on the aggregate of metabolism studies conducted on several crops. The results of these studies indicate that dicamba is rapidly absorbed and translocated by grasses, grapes, black valentine beans, wheat, bluegrass, and soybeans. It is also rapidly absorbed by sugarcane following foliar application but it is very slowly translocated from the leaves to the roots. The metabolism of dicamba in plants proceeds mainly by demethylation and hydroxylation.

The residues of concern in barley, corn, cotton, grasses, oat, proso millet, sorghum, sugarcane, and wheat are dicamba and its 3,6 dichloro 5 hydroxybenzoic acid ( 5 OH dicamba) metabolite; these are the residues currently regulated in 40 CFR § 180.227 ( a)( 1). In asparagus, the residues of concern are dicamba and its 3,6 dichloro 2 hydroxybenzoic acid metabolite [ 40 CFR § 180.227 ( a)( 2)]; the metabolite 3,6 dichloro 2 hydroxybenzoic acid is also referred to as 3,6 dichlorosalicylic acid ( DCSA). The residues of concern in/ on aspirated grain fractions and soybeans are dicamba, 5 OH dicamba, and DCSA [ 40 CFR § 180.227 ( a)( 3)]. The current tolerance definitions are appropriate for all crop commodities with registered uses.

The nature of the residue in animals is adequately understood based on acceptable metabolism studies conducted on ruminants and poultry. The compounds identified in these studies include dicamba, DCSA, and 2 amino 3,6 dichlorophenol. The latter compound was identified only in hen liver at < 1% of total radioactive residues and thus, need not be included in the tolerance expression. The residues of concern in meat, milk, poultry and eggs remain unchanged and consist of dicamba and 3,6 dichloro 2 hydroxybenzoic acid [ 40 CFR § 180.227 ( a)( 2)].

The nature of the residue in rotational crops is understood. The results of an acceptable confined rotational crop study showed that at a plantback interval of 120 days, the total radioactive residues were < 0.01 ppm in/ on samples of collard greens ( a representative of leafy vegetables) and carrots ( a representative of root crops) but were > 0.01 ppm in the matrices of barley ( a Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 3 of 94 representative of small grains). Residue characterization of barley matrices from the 120 day rotation showed that a good percentage of TRR was associated with natural plant constituents ( lignin and cellulose).

Limited and/ or extensive field accumulation studies with dicamba need not be conducted and rotational crop tolerances need not be established provided the registrants are willing to amend all dicamba labels to specify a 120 day plantback interval when dicamba is applied at a maximum seasonal rate of 0.75 lb ae/ A or less. At application rates of 0.75 2.0 lb ae/ A, the labels should specify that only crops with established tolerances can be rotated.

There are adequate plant enforcement methods. The Pesticide Analytical Manual ( PAM) Vol. II lists Method I ( AM 0268A), a GC method with electron capture detection ( GC/ ECD) for the enforcement of dicamba plant tolerances. The sensitivity of the method is listed at 0.05 ppm. An improved plant enforcement method ( GC/ ECD) has resulted from the requirements of the 6/ 30/ 89 Residue Chemistry Chapter of the Dicamba ( SRR). The Chapter requested that Method AM 0691A or B, both of which were modifications to Method I of PAM Vol. II ( AM 0268A), be subjected to an independent laboratory validation ( ILV) because the method procedures included an acid hydrolysis step which increased the extraction efficiency of dicamba residues from various commodities. Method AM 0691B 0593 2 has been subjected to a successful ILV as well as EPA method validation. Pending a re write of the method to incorporate suggested changes/ corrections made by Agency chemists from ACL, the method will be forwarded to FDA for publication in PAM Vol. II. It is noted that Methods AM 0691B 0593 2 and  3 were recently superceded by Method AM 0691B 0297 4, which consists of a more detailed step by step description of the procedures, GC MS confirmatory tests, and additional recovery data. The LOQ for dicamba and 5 OH dicamba is 0.02 ppm.

Several data collection methods were used for the analysis of samples, collected from recent field and processing studies. In essence, these data collection methods were based on or modifications of the improved enforcement method. In conjunction with PP# 4F3041, additional method validation data using Method AM 0691B 0297 4 are required for barley grain and straw at fortification levels of 6 and 15 ppm, respectively, and for wheat straw at 30 ppm because the maximum residues obtained from the respective field trials were not validated at these levels. In addition, the registrants are required to submit additional method validation data using Method AM 0941 1094 0 for soybean seeds at a spike level of 10 ppm. The registrants have committed to generate these data.

For the enforcement of animal commodity tolerances, PAM Vol. II lists Method II, a GC/ ECD method which is identical to Method I. The sensitivity of the method is listed at 0.01 ppm. Based on the results of animal metabolism study, which showed that acid hydrolysis can additionally extract up to 30% of TRR in goat liver, HED is requiring the registrants to revise/ improve Method II to include an acid hydrolysis step and submit additional validation data. Method II should also be re written specifically for the analysis of the parent dicamba and its metabolite 3,6 dichloro 2 hydroxybenzoic acid metabolite in animal matrices. Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 4 of 94 According to FDA's PAM Volume I, Appendix II, dicamba is completely recovered using Section 402 E2 of Protocol B but is only partially recovered using Section 402 E1 of Protocol B. There are no multiresidue methods recovery data for the dicamba metabolites of concern ( 5 OH dicamba and DCSA), and these data are required.

There are adequate storage stability data for a wide variety of crop commodities except on sugarcane molasses. Storage stability data are required for sugarcane molasses to validate the interval and conditions of samples collected from the submitted sugarcane processing study ( MRID 43245204). The available storage stability data indicate that residues of dicamba and its metabolites are reasonably stable under frozen storage conditions in/ on: ( i) field corn forage, silage, grain, and fodder for up to 3 years ( dicamba) and 2 years ( 5 OH dicamba); ( ii) soybean forage for up to 4 months and in refined oil for up to 3 months; ( iii) grass forage and hay for up to 314 and 320 days, respectively; ( iv) asparagus for up to 104 days ( dicamba and DCSA) and 119 days ( 5 OH dicamba); and ( iv) refined white sugar of sugarcane for up to 60 days.

There are no available storage stability data for animal commodities. Samples to be collected from the requested ruminant feeding study should be stored frozen and analyzed promptly ( within a month) to preclude the need for supporting storage stability data. If sample storage will exceed more than a month, then the registrants are required to submit data depicting the storage stability of the parent dicamba and its 3,6 dichloro 2 hydroxybenzoic acid metabolite in milk and ruminant tissues.

The results of the available ruminant feeding study conducted at the feeding level of 400 indicate the maximum total residues of dicamba were 0.32 ppm in milk and 0.9 ppm in kidney. However, a new bovine feeding study conducted at a feeding level of 1000 ppm is currently under review ( MRID 44891303). Based on a cursory review of the study and an estimated maximum theoretical dietary burden of 482 ppm, tolerances for livestock commodities require revision, ranging from a level of 0.2 ppm for fat to 25 ppm for kidney.

A poultry feeding study with dicamba is not required based on the results of the submitted poultry metabolism study. In the poultry study, the TRR levels in eggs, liver, muscle, and fat were all < 0.004 ppm following dosing at 10 ppm ( 1.9x the maximum dietary burden of 5.2 ppm) in the diet for four consecutive days. Residues in eggs plateaued after the first day of dosing ( i. e., there was no accumulation with increasing days of dosing). HED does not anticipate the occurrence of quantifiable residues of dicamba or DCSA in poultry eggs and meat as a result of treating crops with poultry feed items at the maximum use patterns. Therefore, HED concludes that tolerances are not needed in poultry eggs and meat at this time but may be required if additional uses are registered in the future.

Residue studies that were generated by Craven Laboratories had been identified by HED, and a Data Call In Notice was issued on 02/ 94 requesting end use producer( s) of dicamba to conduct new field trials on barley, corn ( field), sorghum, soybean, sugarcane, and wheat. Several residue chemistry studies have been submitted and reviewed in response to the Dicamba DCI Notice. These Craven replacement data along with data submitted for the remainder of crops listed in the Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 5 of 94 Dicamba Master Use Profile were re evaluated in this Residue Chemistry Chapter. Listed below are HED's findings.

Pending label revisions and/ or adjustment of tolerances for some commodities, there are adequate residue data to fulfill reregistration requirements for: asparagus; grass forage and hay; sorghum grain, forage, and stover; and soybean seed and hulls.

It is the current Agency policy to allow label restrictions on the feeding/ grazing of livestock animals on soybean forage and hay, thus, precluding the need for residue data and tolerances for these soybean commodities. HED defers to RD for verifying whether such restrictions exist on product labels. If such restrictions appear on the labels, then residue data and tolerances for soybean forage and hay are not necessary. If no such restrictions appear on the labels, then the registrants are required to propose tolerances for soybean forage and hay; based on the available data, a tolerance level of 0.1 ppm would be appropriate for each soybean commodity. Concomitant with these tolerance proposals, the registrants are required to propose a maximum seasonal rate of 0.5 lb ae/ A for preplant application on soybean grown for forage and hay only.

The submitted data for several crop commodities are inadequate because they do not reflect the maximum use rates listed in Dicamba Master Use Profile. To fulfill reregistration requirements, the registrants are required to submit additional data for the following commodities: barley, grain, hay, and straw; corn, field, grain, forage, and stover; cotton gin by products; sugarcane; and wheat grain and straw. In lieu of submitting additional data for the above listed commodities, the registrants are given the option to rely on the available data provided they revise their product labels for consistency with the reviewed data.

A magnitude of the residue study ( MRID 44891302) in wheat forage and hay has been identified and is currently under review.

There are adequate residue data on the aspirated grain fractions of sorghum, soybean, and wheat. Although the available data support the current tolerance level of 5100 ppm, additional data are required for the aspirated grain fractions of field corn since an examination of BEAD Use Pattern Table indicates that various salt formulations of dicamba may be applied early and late postemergence to the crop.

HED will allow the translation of available/ requested field trial data from some crop commodities to agronomically related commodities with identical uses. The available/ requested data for field corn grain and stover may be translated to pop corn grain and stover. The available/ requested data for wheat grain, forage, hay, and straw may be translated to the respective commodities of proso millet, oat, and rye. Where translation of data is allowed, any HED recommendations with regards to label revisions as well as tolerance reassessment should apply to all respective crop commodities.

Cotton is not included in the list of food/ feed uses which will be supported for reregistration. Therefore, HED is recommending the revocation of the established tolerances for cottonseed and cotton meal. Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 6 of 94 The Agency no longer considers sugarcane forage and fodder to be significant livestock feed items, and these items have been deleted from Table 1 of OPPTS 860.1000. Therefore, the established tolerances for sugarcane forage and fodder should be revoked.

There are acceptable processing studies with dicamba on soybean, sugarcane, and wheat. The soybean processing study resulted in a processing factor of 3.8x for residues of dicamba in soybean hulls but no concentration of residues was observed in other soybean fractions ( meal, crude oil and refined oil). The sugarcane processing study showed that the combined residues were nondetectable (< 0.01 ppm) in refined sugar but concentrated in molasses ( processing factor of 24.4x). The combined residues in soybean hull and sugarcane molasses are expected to exceed the respective established tolerances when the maximum highest average field trial ( HAFT) residues are multiplied by the processing factor; HED is therefore, recommending an upward adjustment to the tolerances. The wheat processing study showed that the combined residues of dicamba and 5 OH dicamba did not concentrate in any wheat processed fractions.

A corn processing study ( MRID 41187301) has been identified and is currently under review. The available wheat grain processing data may be translated to barley and oats. A millet grain processing study is not required since the only processed commodity associated with millet is flour. Endnote 44 of Table 1 OPPTS 860.1000 specifies that millet flour is not produced significantly in the U. S. for human consumption, and residue data are not needed at this time. A sorghum processing study is not required since sorghum flour is used in the U. S. exclusively for drywall, and not as a human food or a feedstuff.

Regulatory Recommendations and Residue Chemistry Deficiencies Listed below is a summary of residue chemistry data deficiencies that must be fulfilled for reregistration. A human health risk assessment is forthcoming.

" Additional method validation data using Method AM 0691B 0297 4; recovery data are needed for barley grain and straw at fortification levels of 6 and 15 ppm, respectively, and for wheat straw at 30 ppm. Additional method validation data using Method AM 0941 1094 0 are also needed for soybean seeds at a spike level of 10 ppm.

" Revise/ improve Method II of PAM Vol. II to include an acid hydrolysis step and submit additional validation data. Method II should also be re written specifically for the analysis of the parent dicamba and its metabolite 3,6 dichloro 2 hydroxybenzoic acid metabolite in animal matrices.

" Multiresidue methods recovery data for the dicamba metabolites of concern ( 5 OH dicamba and DCSA).

" Storage stability data for sugarcane molasses and animal commodities. Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 7 of 94 Cl Cl O OH OCH 3 Cl Cl O O [ NH 2 ( CH 3 ) 2 ]+

OCH 3 " Residue data and tolerances for soybean forage and hay if no feeding restrictions appear on the label.

" Magnitude of the residue data for the following commodities: barley, grain, hay, and straw; corn, field, grain, forage, and stover; sugarcane; and wheat grain and straw. In lieu of submitting additional data for the above listed commodities, the registrants have the option of relying on the available/ submitted data provided they revise their product labels for consistency with the reviewed data.

Background Identification of Active Ingredient The PC code and nomenclature of dicamba and its salts are presented in Table 1. The physicochemical properties of dicamba and its salts are listed in Table 2. PC Codes 029803, 029804, and 029807 are no longer being supported and have been canceled; these dicamba salts are not included in Tables 1 and 2.

Table 1. Dicamba and its Salts Nomenclature PC Code 029801 Chemical structure Common name Dicamba acid Molecular Formula C8H6Cl2O3 Molecular Weight 221.04 IUPAC name 3,6 dichloro o anisic acid CAS name 3,6 dichloro 2 methoxybenzoic acid or 2 methoxy 3,6 dichlorobenzoic acid CAS # 1918 00 9 PC Code 029802 Chemical structure Common name Dicamba dimethylamine salt ( DMA salt)

Molecular Formula C10H13Cl2NO3 Molecular Weight 266.1 Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 Table 1. Dicamba and its Salts Nomenclature 8 of 94 Cl Cl O O  Na +

OCH 3 Cl Cl O O [ NH 3 CH 2 CH 2 OCH 2 CH 2 OH]+

OCH 3 Cl Cl O OCH 3 O [ NH 3 CH( CH 3 ) 2 ]+ CAS # 2300 66 5 PC Code 029806 Chemical structure Common name Dicamba sodium salt ( Na salt)

Molecular Formula C8H5Cl2NaO3 Molecular Weight 243.0 CAS # 1982 69 0 PC Code 128931 Chemical structure Common name Dicamba diglycolamine salt ( DGA salt)

Molecular Formula C12H17Cl2NO5 Molecular Weight 326.18 CAS # 104040 79 1 PC Code 128944 Chemical structure Common name Dicamba isopropylamine salt ( IPA salt)

Molecular Formula C11H15Cl2NO3 Molecular Weight 280.15 CAS # 55871 02 8 Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 Table 1. Dicamba and its Salts Nomenclature 9 of 94 Cl Cl O OCH 3 O  K + PC Code 129043 Chemical structure Common name Dicamba potassium salt ( K salt)

Molecular Formula C8H5Cl2KO3 Molecular Weight 259.1 CAS # 10007 85 9 Table 2. Physicochemical Properties of Dicamba and its Salts Parameter Value Reference Dicamba acid ( PC Code 029801)

Melting point 114 116 ° C ( PAI) 90 100 ° C ( 87% TGAI) SRR Reregistration Standard, 6/ 30/ 89 pH 2.5 3.0 ( 87% TGAI)

Density, bulk density, or specific gravity 1.57 g/ mL at 25 ° C ( 87% TGAI)

Water solubility 0.5 g/ 100 mL at 25 ° C ( PAI)

Solvent solubility g/ 100 mL at 25 ° C ( PAI) dioxane 118.0 ethanol 92.2 isopropyl alcohol 76.0 methylene chloride 26.0 acetone 17.0 toluene 13.0 xylene 7.8 heavy aromatic naphthalene 5.2 Vapor pressure 3.4 x 10 5 mm Hg at 25 ° C ( PAI)

Dissociation constant, pKa 1.97 ( PAI)

Octanol/ water partition coefficient 0.1 ( PAI)

UV/ visible absorption spectrum neutral: 511 ( 275 nm) acidic ( pH 0 1): 1053 ( 281 nm) basic ( pH 13 14): 469 ( 274 nm) RD D266167, 6/ 26/ 00, B. Kitchens Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 Table 2. Physicochemical Properties of Dicamba and its Salts Parameter Value Reference 10 of 94 Dicamba DMA salt ( PC Code 029802)

Melting point 101.0 114.5 ° C D213276, D216855, D216859, D216853, D216857, D216862, D217061, D218789, D218792, D218784, D218787, and D218786, 11/ 21/ 95, L. Cheng pH 3.89 at 25 ° C ( 1% solution)

Density, bulk density, or specific gravity 0.77 g/ mL at 25 ° C ( tap density)

Water solubility 94.5 g/ 100 mL at 25 ° C Solvent solubility N/ A; data for the free acid are representative of the dicamba salts D198000, 5/ 5/ 94, P. Deschamp Vapor pressure Dissociation constant, pKa Octanol/ water partition coefficient KOW = 0.078 D213276, D216855, D216859, D216853, D216857, D216862, D217061, D218789, D218792, D218784, D218787, and D218786, 11/ 21/ 95, L. Cheng UV/ visible absorption spectrum Not available Dicamba Na salt ( PC Code 029806)

Melting point 320 325 ° C RD Memorandum, 9/ 26/ 94, T. Alston pH 7.16 Density, bulk density, or specific gravity 1.03 g/ mL at 25 ° C Water solubility N/ A; data for the organic salts ( DMA, DGA, and IPA) are representative of the Na salt D198000, 5/ 5/ 94, P. Deschamp Solvent solubility N/ A; data for the free acid are representative of the dicamba salts Vapor pressure Dissociation constant, pKa Octanol/ water partition coefficient N/ A; data for the organic salts ( DMA, DGA, and IPA) are representative of the Na salt UV/ visible absorption spectrum Not available Dicamba DGA salt ( PC Code 128931)

Melting point 52.0 85.0 ° C D213276, D216855, D216859, D216853, D216857, D216862, D217061, D218789, D218792, D218784, D218787, and D218786, 11/ 21/ 95, L. Cheng pH 7.60 at 25 ° C ( 1% solution)

Density, bulk density, or specific gravity 0.69 g/ mL at 25 ° C ( tap density)

Water solubility 107 g/ 100 mL at 25 ° C Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 Table 2. Physicochemical Properties of Dicamba and its Salts Parameter Value Reference 11 of 94 Solvent solubility N/ A; data for the free acid are representative of the dicamba salts D198000, 5/ 5/ 94, P. Deschamp Vapor pressure Dissociation constant, pKa Octanol/ water partition coefficient KOW = 0.061 D213276, D216855, D216859, D216853, D216857, D216862, D217061, D218789, D218792, D218784, D218787, and D218786, 11/ 21/ 95, L. Cheng UV/ visible absorption spectrum Not available Dicamba IPA salt ( PC Code 128944)

Melting point 93.5 127.5 ° C D213276, D216855, D216859, D216853, D216857, D216862, D217061, D218789, D218792, D218784, D218787, and D218786, 11/ 21/ 95, L. Cheng pH 4.68 at 25 ° C ( 1% solution)

Density, bulk density, or specific gravity 0.63 g/ mL at 25 ° C ( tap density)

Water solubility 59.6 g/ 100 mL at 25 ° C Solvent solubility N/ A; data for the free acid are representative of the dicamba salts D198000, 5/ 5/ 94, P. Deschamp Vapor pressure Dissociation constant, pKa Octanol/ water partition coefficient KOW = 0.070 D213276, D216855, D216859, D216853, D216857, D216862, D217061, D218789, D218792, D218784, D218787, and D218786, 11/ 21/ 95, L. Cheng UV/ visible absorption spectrum Not available Dicamba K salt ( PC Code 129043)

Melting point Decomposes at 213.5 ° C D213276, D216855, D216859, D216853, D216857, D216862, D217061, D218789, D218792, D218784, D218787, and D218786, 11/ 21/ 95, L. Cheng pH 8.12 at 25 ° C ( 1% solution)

Density, bulk density, or specific gravity 0.88 g/ mL at 25 ° C ( tap density)

Water solubility N/ A; data for the organic salts ( DMA, DGA, and IPA) are representative of the K salt D198000, 5/ 5/ 94, P. Deschamp Solvent solubility N/ A; data for the free acid are representative of the dicamba salts Vapor pressure Dissociation constant, pKa Octanol/ water partition coefficient N/ A; data for the organic salts ( DMA, DGA, and IPA) are representative of the K salt Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 Table 2. Physicochemical Properties of Dicamba and its Salts Parameter Value Reference 12 of 94 UV/ visible absorption spectrum Not available 860.1200 Directions for Use Product List: The different forms of dicamba acid and salts with food/ feed uses, that will be supported for reregistration, include: the dicamba acid ( PC Code 029801), dimethylamine ( DMA) salt ( PC Code 029802), sodium ( Na) salt ( PC Code 029806), isopropylamine ( IPA) salt ( PC Code 128944), diglycolamine ( DGA) salt ( PC Code 128931), and potassium ( K) salt ( PC Code 129043). According to the Status of Pesticides in Registration, Reregistration, and Special Review ( Rainbow Report; 1998), the following salts of dicamba have been cancelled: the diethanolamine salt ( PC Code 029803), monoethanolamine dicamba ( PC Code 029804), and aluminum salt of dicamba ( PC Code 129042).

A 4/ 20/ 05 product registration query of the USEPA/ OPP Chemical Ingredients ( OPPIN) database identified several active end use products ( EPs) containing dicamba acid and/ or salts as the active ingredient. These EPs, as well as all active Special Local Need ( SLN) registrations, are listed below in Table 3.

Table 3. Dicamba End use Products ( EPs) Food/ feed Uses.

EPA Reg. No. Status % AI Product Name Dicamba acid ( PC Code 029801)

000228 00309 Conditionally Registered ( 10 Oct 1995) 10 RIVERDALE VETERAN 10G 000524 00507 Conditionally Registered ( 04 Jun 1999) 4.1 FALLOW MASTER BROAD SPECTRUM HERBICIDE 007969 00142 Conditionally Registered ( 04 Oct 1995) 69.4 SAN 821 H 600 HERBICIDE 007969 00148 Conditionally Registered ( 03 Dec 1996) 10.67 OPTILL HERBICIDE 071369 00030 Conditionally Registered ( 26 Sep 2001) 4.1 NUFARM GLYKAMBA BROAD SPECTRUM HERBICIDE Dimethylamine ( DMA) salt of dicamba ( PC Code 029802) 1 000228 00295 Conditionally Registered ( 22 Aug 1994) 12.82 RIVERDALE VETERAN 720 HERBICIDE 000228 00296 Not listed in OPPIN Summary Report 000352 00614 Conditionally Registered ( 30 Jan 2002) 12.4 DUPONT CIMARRON MAX PART B 000352 00615 Conditionally Registered ( 30 Jan 2002) 12.25 DUPONT CIMARRON MAX HERBICIDE 002217 00639 Conditionally Registered ( 26 Sep 1980) 4.24 TRIMEC 875 HERBICIDE Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 Table 3. Dicamba End use Products ( EPs) Food/ feed Uses.

EPA Reg. No. Status % AI Product Name 13 of 94 007969 00131 Conditionally Registered ( 30 Aug 1962) 48.2 BANVEL HERBICIDE 007969 00133 Conditionally Registered ( 01 Apr 1974) 12.4 WEEDMASTER HERBICIDE 051036 00289 Conditionally Registered ( 14 May 1997) 48.2 DICAMBA DMA 4# AG 051036 00308 Conditionally Registered ( 19 Oct 1998) 12.4 BANVEL + 2,4 D Sodium ( Na) salt of dicamba ( PC Code 029806)

000100 00923 Conditionally Registered ( 25 Sep 1998) 43.9 NORTHSTAR HERBICIDE 000100 00927 Conditionally Registered ( 14 Dec 1998) 55 RAVE HERBICIDE 000241 00359 Conditionally Registered ( 07 Feb 1995) 61.9 RESOLVE SG HERBICIDE 000241 00384 Conditionally Registered ( 17 Mar 1998) 58.9 AC 513,995 DG HERBICIDE 007969 00135 Conditionally Registered ( 25 Apr 1986) 23.15 BANVEL SGF HERBICIDE 007969 00140 Conditionally Registered ( 30 Jun 1994) 77 SAN845H HERBICIDE 007969 00150 Conditionally Registered ( 28 Jan 1999) 55 DISTINCT HERBICIDE 007969 00166 Conditionally Registered ( 26 Feb 1998) 69.3 CELEBRITY HERBICIDE 007969 00175 Conditionally Registered ( 04 Aug 1999) 46.6 CELEBRITY PLUS HERBICIDE 033906 00011 Conditionally Registered ( 04 Feb 2002) 55 NC 398 WG 042750 00043 Conditionally Registered ( 07 Oct 1998) 23.15 ALBAUGH DICAMBA SODIUM SALT 051036 00290 Conditionally Registered ( 01 Aug 1997) 23.15 DICAMBA DMA 2# AG Isopropylamine ( IPA) salt of dicamba ( PC Code 128944)

000524 00390 Conditionally Reregistered ( 22 May 1997) 7 FALLOW MASTER HERBICIDE 007969 00138 Conditionally Registered ( 07 Jan 1988) 40.32 IPA SALT OF DICAMBA 042750 00063 Conditionally Registered ( 31 May 2001) 7 FALLOW STAR Diglycolamine ( DGA) salt of dicamba ( PC Code 128931)

000100 00975 Conditionally Registered ( 25 Jan 2001) 28.4 TD HERBICIDE Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 Table 3. Dicamba End use Products ( EPs) Food/ feed Uses.

EPA Reg. No. Status % AI Product Name 14 of 94 007969 00137 Conditionally Registered ( 23 Sep 1987) 56.8 CLARITY HERBICIDE Potassium ( K) salt of dicamba ( PC Code 129043)

007969 00136 Conditionally Registered ( 25 Apr 1986) 13.42 MARKSMAN HERBICIDE 033658 00016 Conditionally Registered ( 16 Aug 2000) 13.45 STRATOS DICAMBA+ ATRAZINE AGRICULTURAL HERBICIDE 042750 00041 Conditionally Registered ( 22 May 1998) 13.42 DICAMBAZINE 051036 00307 Conditionally Registered ( 13 Oct 1998) 13.42 BANVEL + ATRAZINE 1 Includes SLNs CO90000200, CO99001200, CO99001300, and CO99001400.

Use Pattern Profile: The Agency's Special Review and Reregistration Division ( SRRD) issued a Use Closure Memorandum for Dicamba ( Case No. 0065) on 8/ 2/ 05 in an attempt to provide use information that will be incorporated into the preliminary risk assessment for dicamba. The Dicamba Use Closure Memo resulted from the 11/ 4/ 04 SMART meeting and subsequent discussions and review of product labels with the following registrants: Albaugh, Inc., BASF Corporation, Gharda USA, Inc., and Syngenta Crop Protection, Inc. The Closure Memo serves as the Agency's record of common understanding on the uses of dicamba that will be supported and used in risk assessments, including currently registered product information. The registrants intend to support all currently registered uses described in the Use Closure Memorandum for Dicamba and all currently registered products.

The Dicamba Use Closure Memos's list of food/ feed uses is reproduced in Table 4 with minor alteration to include information pertaining to preharvest intervals ( PHI). The PHI information, added in the last column of Table 4, was obtained from the 2002 Food/ Feed Use Patterns Summary for dicamba acid and salts prepared by a contractor for BEAD; the BEAD Use Patterns Tables are presented in Appendix 1. Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 15 of 94 Table 4. Dicamba Food/ Feed Use Profile.

Use Sites Forms 1 Max App. Rate ( lb ae/ A) Max App. Rate ( lb ae/ A/ year) PHI/ PGI/ PFI/ PSI 2 Agricultural Crops/ Soils DMA Salt, Na Salt 2.0 2.0 Agricultural Fallow/ Idleland All 2.0 2.0 Na salt: 37 day PHI ( dry hay and grain) and 30 day PSI; IPA salt: 56 day PFI/ PGI Agricultural/ Farm Premises DMA Salt, DGA Salt 1.0 1.0 Agricultural/ Farm Structures/ Buildings and Equipment DMA Salt 1.0 1.0 Asparagus DMA Salt, Na Salt, DGA Salt 0.5 0.5 DMA salt, Na salt, and DGA salt: 1 day PHI Barley 3 DMA Salt, Na Salt, DGA Salt, IPA Salt 0.25 0.38 Dicamba acid: 15 day PHI; DMA salt: 30 day PSI, 37 day PHI ( dry hay), and 7 day PGI ( dairy animals); Na salt: 37 day PHI ( dry hay and grain) and 30 day PSI; DGA salt: 7 day PHI; IPA salt: 56 day PFI/ PGI Corn ( field, pop, seed, silage) DMA Salt, Na Salt, DGA salt, K Salt 0.5 0.75 Corn unspecified  Dicamba acid: 40 day PFI/ PGI and Na salt: 30 to 32 day PHI and 30 day PGI; Corn  DMA salt: 30 day PSI, 37 day PHI ( dry hay), and 7 day PGI ( dairy animals); Field corn  Dicamba acid: 40 day PFI/ PGI and Na salt: 30 to 32 day PHI, 45 day PHI ( fodder), 60 day PHI ( grain), and 30 day PFI/ PGI Pop corn  Dicamba acid: 40 day PFI/ PGI and Na salt: 45 day PHI ( fodder), 60 day PHI ( grain), and 30 day PFI/ PGI Cotton Dimethylamine Salt, DGA 0.25 2.0 Hay DMA Salt, Na Salt, DGA Salt 2.0 4 2.0 DMA salt: 30 day PSI, 7 to 37 day PHI ( dry hay), and 7 day PGI ( dairy animals)

Millet ( Proso) 3 DMA Salt 0.125 0.125 Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 Table 4. Dicamba Food/ Feed Use Profile.

Use Sites Forms 1 Max App. Rate ( lb ae/ A) Max App. Rate ( lb ae/ A/ year) PHI/ PGI/ PFI/ PSI 2 16 of 94 Oats DMA Salt, Na Salt, DGA Salt 0.125 1.0 Dicamba acid: 15 day PHI; DMA salt: 30 day PSI, 37 day PHI ( dry hay), and 7 day PGI ( dairy animals); Na salt: 37 day PHI ( dry hay); IPA salt: 56 day PFI/ PGI Pastures 5 DMA Salt, Na Salt, DGA Salt 2.0 2.0 DMA salt: 30 day PSI, 37 day PHI ( dry hay), 7 to 70 day PHI ( dry hay), 7 day PGI ( dairy animals), and 40 day PGI Na salt: 30 day PSI and 37 day PHI ( dry hay and grain); DGA salt: 30 day PSI and 7 day PGI ( dairy animals)

7.7 7.7 Rangeland 5 DMA Salt, Na Salt, DGA Salt 2.0 2.0 DMA salt: 30 day PSI, 37 day PHI ( dry hay), 7 to 70 day PHI ( dry hay), 7 day PGI ( dairy animals), and 40 day PGI; Na salt: 30 day PSI and 37 day PHI ( dry hay and grain); DGA salt: 30 day PSI and 7 day PGI ( dairy animals)

7.7 7.7 Rye DMA Salt 0.5 1.0 DMA salt: 30 day PSI, 37 day PHI ( dry hay), and 7 day PGI ( dairy animals)

Sorghum All 0.2748 0.5 Dicamba acid: 15 day PHI and 40 day PFI/ PGI; DMA salt: 30 day PSI, 37 day PHI ( dry hay), and 7 day PGI ( dairy animals) Na salt: 30 day PGI and PHI; IPA salt: 56 day PFI/ PGI; K salt: 21 day PFI/ PGI and 30 to 37 day PHI Soybean Sodium Salt, DGA 2.0 2.0 Sudangrass DMA Salt 0.5 ( as listed for hay) 1.0 DMA salt: 30 day PSI, 37 day PHI ( dry hay), and 7 day PGI ( dairy animals)

Sugarcane DMA Salt, Na Salt, DGA salt 2.8 2.8 DMA salt: 30 day PSI, 37 day PHI ( dry hay), and 7 day PGI ( dairy animals) Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 Table 4. Dicamba Food/ Feed Use Profile.

Use Sites Forms 1 Max App. Rate ( lb ae/ A) Max App. Rate ( lb ae/ A/ year) PHI/ PGI/ PFI/ PSI 2 17 of 94 Wheat 3 DMA Salt, Na Salt, DGA Salt, IPA Salt 0.5 1.0 Dicamba acid: 15 day PHI; DMA salt: 30 day PSI, 37 day PHI ( dry hay), 7 to 14 day PHI, and 7 day PGI ( dairy animals) Na salt: 30 day PSI and 37 day PHI ( dry hay and grain) IPA salt: 56 day PFI/ PGI 1 There are five forms of dicamba used in this Master Label: Dimethylamine [ DMA] Salt ( PC Code 029802), Sodium [ Na] Salt ( PC Code 029806), Diglycolamine [ DGA] ( PC Code 128931), Isopropylamine Salt [ IPA] ( PC Code 128944), and Potassium [ K] Salt ( PC Code 129043). 2 PHI = Preharvest interval; PGI = Pregrazing interval; PFI = Prefeeding interval; PSI = Preslaughter interval. This information was obtained from the summaries of the food/ feed use patterns of dicamba as prepared by BEAD ( see Appendix 1). 3 SLN registration CO990001300 is for small grains at 1.0 lbs ae/ A. Based on Agency data, barley, millet, and wheat are listed as small grains. 4 Based on label ( EPA Reg. Nos. 51036 289 and 7969 131). 5 Label ( EPA Reg. No. 100 884) lists 7.7 lb ae/ A as the maximum rate for spot treatment for pasture and rangeland uses. The 2.0 lbs ae/ A is what the registrant stated at the SMART meeting as the rate they intended to support.

Conclusions: The available residue chemistry data for dicamba acids and/ or salts were reevaluated in this Residue Chemistry Chapter for adequacy in fulfilling the maximum use patterns listed for each crop in the 8/ 2/ 05 Dicamba Use Closure Memorandum. For sugarcane, the maximum seasonal rates listed in the Dicamba Use Closure Memo are not supported by adequate field trial data. To satisfy reregistration requirements, this Chapter is requiring the registrants to submit additional data. Alternatively, the registrants are given the option of revising product labels for consistency with the reviewed data. In addition, label revisions are required to specify the appropriate rotational crop restrictions based on the submitted confined rotational crop study.

HED notes that labels of basic producers have been revised to specify that aerial applications should be made in spray volumes of > 2 gallons/ A precluding the need for residue data reflecting ultra low volume application ( ULV). HED requests RD to verify that the labels of non basic producers are also amended to specify this exact information. Finally, HED wishes to comment on certain food/ feed sites listed in the 8/ 2/ 05 Dicamba Use Closure Memorandum. The sites ` Agricultural Crops/ Soils' and ` Agricultural Fallow/ Idleland' are very broad uses and should be deleted unless the registrants submit residue data on representative commodities of all crop groups. The sites ` Agricultural/ Farm Premises' and ` Agricultural/ Farm Structures/ Buildings and Equipment' are classified as nonfood uses since dicamba application on these sites would not be expected to result in significant dicamba residues that could eventually be consumed.

A tabular summary of the residue chemistry science assessments for the reregistration of dicamba is presented in Table 5. The conclusions listed in Table 5 regarding the reregistration eligibility of Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 18 of 94 the food/ feed uses of dicamba are based on the food/ feed uses summarized in Table 4. When enduse product DCIs are developed, RD should require that all end use product labels ( e. g., MAI labels, SLNs, and products subject to the generic data exemption) be amended such that they are consistent with the master label. Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 19 of 94 Table 5. Residue Chemistry Science Assessment for the Reregistration of Dicamba.

GLN Data Requirements Tolerances ( ppm) [ 40 CFR § 180.227] Additional Data Needed? MRID Nos. 1 860.1200: Directions for Use N/ A = Not Applicable Yes2 See Appendix 1 860.1300: Nature of the Residue  Plants N/ A No 00022745 00022753 00025344 00036921 00079708 00079747 00102945 00118473 406428013 860.1300: Nature of the Residue  Animals N/ A No 00077779 00145248 432452014 432452024 434617015 435542055 860.1340: Residue Analytical Method  Plant Commodities N/ A Yes 6 00028263 00079736 00088173 00162206 40233501 428832017 438140027 438141038 438141048  Animal Commodities N/ A Yes 9 00079744 860.1360: Multiresidue Method N/ A Yes 10 PAM Vol. I 860.1380: Storage Stability Data  Plant Commodities N/ A Yes11 405479113 40663801 4324520412 4324520512 4324520612 4327450112 4337070113 438141028 4386660114  Animal Commodities N/ A Yes15 860.1400: Magnitude of the Residue  Water, Fish, and Irrigated Crops N/ A No 860.1460: Magnitude of the Residue  Food Handling N/ A No 860.1480: Magnitude of the Residue  Meat, Milk, Poultry, Eggs  Milk and the Fat, Meat, and Meat Byproducts of Cattle, Goats, Hogs, Horses, and Sheep 0.2 for fat, meat, and meat byproducts; 0.3 for milk; 1.5 for kidney and liver Yes16 00079742 00116671 4489130317  Eggs and the Fat, Meat, and Meat Byproducts of Poultry None established No 00148127 Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 Table 5. Residue Chemistry Science Assessment for the Reregistration of Dicamba.

GLN Data Requirements Tolerances ( ppm) [ 40 CFR § 180.227] Additional Data Needed? MRID Nos. 1 20 of 94 860.1500: Crop Field Trials Legume Vegetables ( Crop Group 6)

 Soybean seed 10.0 No18 00102944 438141018 4408930714 Foliage of Legume Vegetables ( Crop Group 7)

 Soybean forage and hay None established No19 00075729 00102944 438141018 4408930714 Cereal Grains ( Crop Group 15)

 Barley grain 6.0 No 00028252 00162206 4408930414  Corn, field, grain 0.5 No 00015636 00015637 00015640 00015641 00015642 00015786 00016435 00016436 00016437 00016438 00022612 00022613 00022618 00023584 00023684 00025364 00025383 00028269 00075715 00088172 4408930314  Corn, pop, grain 0.5 No20  Millet grain 0.5 No20 00025330  Oat grain 0.5 No20 00023687 00028252  Rye grain None established No20  Sorghum grain 3.0 No21 00022622 00078448 4324520312 4408930622  Wheat grain 2.0 Yes23 00004541 00004566 00023687 00025394 00028398 00162206 40663801 4408930514 Forage, Fodder, and Straw of Cereal Grains ( Crop Group 16)

 Barley hay and straw 2.0 for hay; 15.0 for straw No 00028252 00162206 4408930414 Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 Table 5. Residue Chemistry Science Assessment for the Reregistration of Dicamba.

GLN Data Requirements Tolerances ( ppm) [ 40 CFR § 180.227] Additional Data Needed? MRID Nos. 1 21 of 94  Corn, field, forage and stover 0.5 for corn forage and stover; 3.0 for field corn forage and stover Yes24 00015636 00015637 00015640 00015641 00015642 00015786 00016435 00016436 00016437 00016438 00022612 00022613 00022618 00023584 00023684 00025364 00025383 00028269 00075715 00088172 4408930314  Corn, pop, stover 3.0 No23  Millet forage, hay, and straw 0.5 for straw No23 00025330  Oat forage, hay, and straw 80 for forage; 20 for hay; 0.5 for straw No23 00023687 00028252  Rye forage and straw None established No23  Sorghum forage and stover 3.0 for forage and stover No25 00022622 00078448 4324520312 4408930625  Wheat forage, hay, and straw 80.0 for forage; 20.0 for hay; 30.0 for straw Yes26 00004541 00004566 00023687 00025394 00055662 00162206 4327450127 4408930514 4489130228 Grass, Forage, Fodder, and Hay ( Crop Group 17)  Pasture and rangeland grasses 125 for forage; 200 for hay No29 00028173 00028200 00028267 00028268 4337070130 Miscellaneous Commodities  Asparagus 4.0 No31 00025338 4324520612 4342580312  Aspirated grain fractions 5100 Yes32 4324520512 438141028 4408930514  Cotton, undelinted seed, and gin byproducts 5.0 for cottonseed No33 4381400131  Sugarcane 0.1 for cane, fodder, and forage Yes34 00030701 00079738 00149626 4408930225 860.1520: Processed Food/ Feed  Barley grain None established No23  Corn grain None established Yes35 4118730136  Cotton 5.0 for meal No37  Millet grain None established No37 Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 Table 5. Residue Chemistry Science Assessment for the Reregistration of Dicamba.

GLN Data Requirements Tolerances ( ppm) [ 40 CFR § 180.227] Additional Data Needed? MRID Nos. 1 22 of 94  Oat None established No23  Sorghum None established No38  Soybean 13.0 for hulls No 438141028  Sugarcane 2.0 for molasses No39 4324520412  Wheat None established No 4066380140 4267590141 860.1650: Submittal of Analytical Standards N/ A Yes42 860.1850: Confined Accumulation in Rotational Crops Not applicable No 4197200143 4369860144 860.1900: Field Accumulation in Rotational Crops None established No45 Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 23 of 94 1. Unless otherwise specified by an endnote, all references were originally reviewed in the 8/ 12/ 83 Residue Chemistry Chapter of the Dicamba Registration Standard and re summarized in the 6/ 30/ 89 Residue Chemistry Chapter of the Dicamba ( SRR) Registration Standard.

2. For sugarcane, the maximum seasonal rates listed in the 8/ 2/ 05 Dicamba Use Closure Memorandum are not supported by adequate field trial data. To satisfy reregistration requirements, this Chapter is requiring the registrants to submit additional data. Alternatively, the registrants are given the option of revising product labels for consistency with the reviewed data. In addition, label revisions are required to specify the appropriate rotational crop restrictions based on the submitted confined rotational crop study.

HED requests RD to verify that the labels of non basic producers are amended to specify that aerial applications should be made in spray volumes of > 2 gallons/ A; this would preclude the need for residue data reflecting ultra low volume application ( ULV).

HED wishes to comment on certain food/ feed sites listed in the 8/ 2/ 05 Dicamba Use Closure Memorandum. The sites ` Agricultural Crops/ Soils' and ` Agricultural Fallow/ Idleland' are very broad uses and should be deleted unless the registrants submit residue data on representative commodities of all crop groups. The sites ` Agricultural/ Farm Premises' and ` Agricultural/ Farm Structures/ Buildings and Equipment' are classified as nonfood uses since dicamba application on these sites would not be expected to result in significant dicamba residues that could eventually be consumed.

3. DEB Nos. 4424 and 4425, 5/ 18/ 89, E. Haeberer.

4. DP Barcode D204482, 3/ 7/ 96, L. Cheng.

5. DP Barcode D226526, 6/ 24/ 96, D. Miller. [ This memo acknowledges receipt of the cited studies relevant to confirmation of residues using the enforcement analytical method. This HED memo stated that the study is presently in house awaiting review.]

6. In conjunction with PP# 4F3041, additional method validation data using Method AM 0691B 0297 4 are required for barley grain and straw at fortification levels of 6 and 15 ppm, respectively, and for wheat straw at 30 ppm because the maximum residues obtained from the respective field trials were not validated at these levels. In addition, the registrants are required to submit additional method validation data using Method AM 0941 1094 0 for soybean seeds at a spike level of 10 ppm. The registrants have committed to generate these data.

7. DP Barcodes D220469, D220471, D220473, and D220430, 5/ 2/ 96, F. Griffith; DP Barcode D227359, 6/ 27/ 96, F. Griffith; and DP Barcode D194776, 12/ 14/ 93, D. Miller.

8. DP Barcodes D223283, D223292, D223300, D223311, D223316, D223320, D223355, D223356, D223361, D223363, D223373, D223374, D223380, and D223383, 7/ 29/ 96, S. Knizner, W. Dykstra, and C. Lewis.

9. The Pesticide Analytical Manual ( PAM) Vol. II lists Method II, a GC/ ECD method which is identical to Method I, for the enforcement of dicamba animal tolerances. Based on the results of animal metabolism study, which showed that acid hydrolysis can additionally extract up to 30% of TRR in goat liver, HED is requiring the registrants to revise/ improve Method II to include an acid hydrolysis step and submit additional validation data for animal matrices using the improved method. Method II should also be rewritten specifically for the analysis of the parent dicamba and its metabolite 3,6 dichloro 2 hydroxybenzoic acid metabolite in animal matrices.

10. There are no multiresidue methods recovery data for the dicamba metabolites of concern ( 5 OH dicamba and DCSA), and these data are required. The registrants are required to follow the directions for the Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 24 of 94 protocols found in PAM Vol. I, Appendix II under paragraph ( d)( 1) of OPPTS 860.1360 GLN, starting with the decision tree for multiresidue methods testing and the accompanying guidance found in the suggestions for producing quality data.

11. Storage stability data are required for sugarcane molasses to validate the interval and conditions ( 64 days, < 1 ° C) of samples collected and analyzed from the submitted sugarcane processing study ( MRID 43245204).

12. DP Barcodes D204488, D204809, and D209229, 7/ 14/ 97, L. Cheng.

13. DP Barcode D207649, 3/ 11/ 96, L. Cheng.

14. DP Barcode D228703, 7/ 16/ 98, S. Chun.

15. There are no available storage stability data for animal commodities. There is a ruminant feeding study currently under review. If the samples were stored frozen and analyzed promptly ( within a month), then supporting storage stability data would not be required. Otherwise storage stability studies of the parent dicamba and its 3,6 dichloro 2 hydroxybenzoic acid metabolite in milk and ruminant tissues would be required.

16. A new bovine feeding study ( MRID 44891303) is currently under review.

17. This study is currently under review.

18. For consistency with the reviewed data, HED will have no objection if the registrants revise their labels to specify a maximum seasonal rate of 2.5 lb ae/ A on soybeans since this rate is supported by adequate data. The available data indicate that the established tolerance of 10 ppm for soybean seed will not be exceeded when representative salt formulations of dicamba are applied at a slightly exaggerated total rate of 2.5 lb ae/ A.

19. It is the current Agency policy to allow label restrictions on the feeding/ grazing of livestock animals on soybean forage and hay, thus, precluding the need for residue data and tolerances for these soybean commodities. HED defers to RD for verifying whether such restrictions exist on product labels. If such restrictions appear on the labels, then residue data and tolerances for soybean forage and hay are not necessary. If no such restrictions appear on the labels, then the registrants are required to propose tolerances for soybean forage and hay at 0.1 ppm each. Concomitant with these tolerance proposals, the registrants are required to propose a maximum seasonal rate of 0.5 lb ae/ A for preplant application on soybean grown for forage and hay only.

20. HED will allow the translation of available/ requested field trial data from some crop commodities to agronomically related commodities with similar uses. The available/ requested data for field corn grain and stover may be translated to pop corn grain and stover. The available/ requested data for wheat grain, forage, hay, and straw may be translated to the respective commodities of proso millet, oat, and rye. Finally, the available wheat grain processing data may be translated to barley and oats. Where translation of data is allowed, any HED recommendations with regards to label revisions as well as tolerance reassessment should apply to all respective crop commodities.

21. HED is recommending label revision to specify a 30 day PHI for sorghum grain for consistency with the reviewed data.

22. DP Barcodes D304019, D306687 D306690, x/ x/ 05, C. Olinger.

23. The registrants are required to submit a complete set of residue data on wheat grain reflecting a maximum seasonal rate of 1.0 lb ae/ A. Alternatively, the registrants may rely on the available data provided they are Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 25 of 94 willing to revise product labels for consistency with the reviewed data. If the registrants elect to choose the latter option, then they will be required to revise product labels to specify a maximum seasonal rate of 0.5 lb ae/ A. The existing tolerance of 2.0 ppm for wheat grain will be considered adequate if the registrants elect to revise product labels.

24. The registrants are required to submit additional data on field corn forage and stover reflecting a maximum seasonal rate of 0.75 lb ae/ A. Alternatively, the registrants may rely on the available data provided they are willing to revise product labels for consistency with the reviewed data. If the registrants elect to choose the latter option, then they will be required to revise product labels to specify a maximum seasonal rate of 2.75 lb ae/ A, a 39 day PHI/ PGI for forage, and a 66 day PHI for stover. The existing tolerances of 3.0 ppm for field corn forage and fodder would remain adequate if the registrants elect to revise product labels.

25. For consistency with the reviewed data, label revisions are required to specify: ( i) a 20 day PHI and a maximum single/ seasonal rate of 0.25 lb ae/ A for sorghum forage; and ( ii) a 30 day PHI for sorghum fodder ( stover) at a maximum seasonal rate of 0.5 lb ae/ A. Following an examination of use directions for sorghum, HED will allow a lower use rate for forage since this RAC will be harvested prior to the second crop application.

26. A magnitude of the residue study ( MRID 44891302) in wheat forage and hay is currently under review.

The registrants are required to submit additional data on wheat straw reflecting a maximum seasonal rate of 1.0 lb ae/ A. Alternatively, the registrants may rely on the available data provided they are willing to revise product labels for consistency with the reviewed data. If the registrants elect to choose the latter option, then they will be required to revise product labels to specify a maximum seasonal rate of 0.5 lb ae/ A and a 7 day PHI for wheat straw. The existing tolerance of 30 ppm for wheat straw will be considered adequate if the registrants elect to revise product labels.

27. DP Barcodes D220430, D220469, D220471, and D220473, 5/ 2/ 96, F. Griffith.

28. A magnitude of the residue study ( MRID 44891302) in wheat forage and hay is currently under review.

29. HED is requesting RD to verify that all dicamba labels specify a 0 day PHI/ PGI for grass forage and a 7 day PHI for grass hay when applied at a maximum of 2.0 lb ae/ A. In addition, HED is recommending the removal of the spot treatment use on pastures and rangeland at 7.7 lb ae/ A ( from EPA Reg. No. 100 884) because there are no available data supporting this use rate; alternatively, the registrants may submit data to support this application rate.

30. This grass forage and hay submission was initially reviewed in a 3/ 11/ 96 memo ( DP Barcode 207649, L Cheng) to fulfill reregistration requirements. The study was re evaluated in conjunction with PP# 6F4604: ( i) DP Barcodes D220469, D220471, D220473, and D220430, 5/ 2/ 96, F. Griffith; and ( ii) DP Barcodes D228694 and D239967, 6/ 25/ 98, S. Chun.

31. There are adequate residue data on asparagus. However, HED requests RD to verify that the label PHI for asparagus is 24 hours or 1 day for consistency with the reviewed data.

32. Data on the aspirated grain fractions of field corn are required since an examination of the BEAD Use Pattern Table indicates that various salt formulations of dicamba may be applied early and late postemergence to the crop. The required data on the aspirated grain fractions of corn should analyze for all residues of concern ( parent, 5 OH dicamba, and DCSA).

33. It does not appear that the registrants are supporting uses on cotton. Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 26 of 94 34. The registrants are required to submit additional data on sugarcane reflecting a maximum single/ yearly rate of 2.8 lb ae/ A. Alternatively, the registrants may rely on the available data provided they are willing to revise product labels for consistency with the reviewed data. If the registrants elect to choose the latter option, then they will be required to revise product labels to specify a maximum seasonal rate of 2.0 lb ae/ A and an 87 day PHI for sugarcane. The existing tolerance of 0.1 ppm for sugarcane is inadequate and HED is recommending that it be reassessed at 0.3 ppm if the registrants elect to revise product labels as detailed above.

35. The registrants have not responded to the requirement of the Dicamba SRR ( 6/ 89) to submit a field corn grain processing study. This requirement remains outstanding. ( Note: A corn processing study ( MRID 41187301) has been identified and will be reviewed.)

36. A corn processing study ( MRID 41187301) has been identified and will be reviewed.

37. According to Table 1 of OPPTS 860.1000, the only processed commodity associated with millet is flour. Endnote 44 of Table 1 specify that millet flour is not produced significantly in the U. S. for human consumption, and residue data are not needed at this time.

38. The Dicamba SRR ( 6/ 89) required a sorghum processing study depicting the combined residues of dicamba and its hydroxy metabolite in milled products ( flour and starch) from sorghum grain bearing measurable, weathered residues. In response, the registrant submitted a protocol ( S. Knizner, 6/ 11/ 93) and a rebuttal to the review of the protocol ( R. Perfetti, 10/ 20/ 93). The Agency concluded that residue data are not required for sorghum flour or starch. Based on this previous HED determination, a sorghum processing study is not required for reregistration.

39. Pending submission of supporting storage stability data for sugarcane molasses, an adequate sugarcane processing study is available.

40. DEB Nos. 3968, 3969, 4018, and 4019, 11/ 4/ 88, F. Griffith.

41. DP Barcodes D189039, D189041, and D189043, 4/ 23/ 93, L. Cheng.

42. Analytical standards for dicamba acid, DMA salt of dicamba, and Na salt of dicamba are currently available ( as of 5/ 6/ 2005) in the National Pesticide Standards Repository; however, no standards are available for 5 OH dicamba and DCSA. Analytical reference standards of dicamba and its regulated metabolites must be supplied, and supplies replenished as requested by the Repository. The reference standards should be sent to the Analytical Chemistry Lab, which is located at Fort Meade, to the attention of either Theresa Cole or Frederic Siegelman at the following address:

USEPA National Pesticide Standards Repository/ Analytical Chemistry Branch/ OPP 701 Mapes Road Fort George G. Meade, MD 20755 5350 ( Note that the mail will be returned if the extended zip code is not used.)

43. DP Barcode D197629, 2/ 16/ 96, L. Cheng.

44. DP Barcodes D228694 and D239967, 6/ 25/ 98, S. Chun.

45. Limited and/ or extensive field accumulation studies with dicamba need not be conducted and rotational crop tolerances need not be established provided the registrants are willing to amend all dicamba labels with food/ feed use claims to specify a 120 day plantback interval when dicamba is applied at a maximum seasonal rate of 0.75 lb ae/ A or less. At application rates of 0.75 2.0 lb ae/ A, the labels should specify that only the crops with established dicamba tolerances can be rotated. Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 27 of 94 Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 28 of 94 Cl Cl O OH OCH 3 Cl Cl O OH O H OCH 3 Cl Cl O OH OH SUMMARY OF SCIENCE FINDINGS 860.1300 Nature of the Residue  Plants The nature of the residue in plants is adequately understood. The residues of concern in barley, corn, cotton, grasses, oat, proso millet, sorghum, sugarcane, and wheat are dicamba and its 3,6 dichloro 5 hydroxybenzoic acid ( 5 OH dicamba) metabolite; these are the residues currently regulated in 40 CFR § 180.227 ( a)( 1). In asparagus, the residues of concern are dicamba and its 3,6 dichloro 2 hydroxybenzoic acid metabolite [ 40 CFR § 180.227 ( a)( 2)]; the metabolite 3,6 dichloro 2 hydroxybenzoic acid metabolite is also referred to as 3,6 dichlorosalicylic acid ( DCSA). The residues of concern in/ on aspirated grain fractions and soybeans are dicamba, 5 OH dicamba, and DCSA [ 40 CFR § 180.227 ( a)( 3)]. The current tolerance definitions are appropriate for all crop commodities with registered uses. The chemical names and structures of dicamba and its regulated metabolites are depicted below in Figure 1.

Figure 1. Chemical names and structures of dicamba and its metabolites.

Dicamba ( 3,6 dichloro o anisic acid) 5 hydroxy dicamba ( 3,6 dichloro 5 hydroxy o anisic acid) DCSA ( 3,6 dichloro 2 hydroxybenzoic acid or 3,6 dichlorosalicylic acid)

The available plant metabolism studies with dicamba were originally reviewed in the 8/ 12/ 83 Residue Chemistry Chapter of the Dicamba Registration Standard and re summarized in the 6/ 30/ 89 Residue Chemistry Chapter of the Dicamba ( SRR) Registration Standard. The Dicamba SRR concluded that dicamba is rapidly absorbed and translocated by grasses ( MRID 00022753), grapes ( MRID 00022745), black valentine beans ( MRID 00079708), wheat and bluegrass ( MRID 00036921), and soybeans ( MRID 00102945). Dicamba is also rapidly absorbed by sugarcane following foliar application but it is very slowly translocated from the leaves to the roots ( MRID 00079747). Dicamba is metabolized in plants mainly by demethylation and hydroxylation.

860.1300 Nature of the Residue  Livestock MRID 43245201 ( Ruminant) ( DP Barcode D204482, 3/ 7/ 96, L. Cheng) MRID 43245202 ( Poultry) ( DP Barcode D204482, 3/ 7/ 96, L. Cheng)

The nature of the residue in animals is adequately understood based on acceptable metabolism studies conducted on ruminants and poultry. The compounds identified in these studies include dicamba, 3,6 dichlorosalicylic acid ( DCSA) and 2 amino 3,6 dichlorophenol. The latter compound was identified only in hen liver at < 1% and thus, need not be included in the tolerance expression. The residues of concern in meat, milk, poultry and eggs remain unchanged and Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 29 of 94 consist of dicamba and 3,6 dichloro 2 hydroxybenzoic acid [ 40 CFR § 180.227 ( a)( 2)]. The chemical structures of dicamba residues of concern in animals are depicted in Figure 1. The salient features of the reviewed animal metabolism studies are summarized below.

Ruminants: In a goat metabolism study ( MRID 43245201), [ 14C] dicamba was administered orally once daily for four consecutive days to two goats ( Goat A and Goat B) at a dose equivalent to 5.91 or 630.8 ppm, respectively in the diet. The test substance had a radiochemical purity of 99% and a specific activity of 3.99 mCi/ mmol. The dose rates were based on actual body weights of 41 and 39 kg for goats A and B, respectively, and a feed consumption of approximately 63 68 grams of feed/ kg of body weight/ day. Only analyses of tissue samples from Goat A were presented. The 5.91 ppm dose is substantially below the estimated maximum theoretical dietary exposure of 1153.63 ppm ( see Table 6).

Milk was collected twice daily. Within 24 hours following the final dose, the test animals were sacrificed and kidney, liver, muscle, and fat were collected. Samples were stored frozen ( 20 ° C) until analysis. In a follow up submission ( No MRID No.; DP Barcode D226526, 6/ 24/ 96, D. Miller), the registrant stated that in no case were samples stored for longer than 6 months ( from date of collection) prior to preliminary chromatographic analyses. The follow up review concluded that there are no storage stability concerns associated with the previously submitted metabolism studies.

The total radioactive residues ( TRR, expressed as dicamba equivalents) in samples taken from the treated goat were: 0.0007 0.0020 ppm in milk, 0.0105 ppm in fat, 0.0536 ppm in kidney, 0.0141 ppm in liver, and 0.0040 ppm in muscle. Kidney, liver, and fat samples were subjected to residue extraction procedures using organic solvents, and the nonextractable residues were acid hydrolyzed to release bound residues. The extractable residues were analyzed by TLC and HPLC, and the identity of dicamba was confirmed by GC/ MS.

Approximately 95 100% of the TRRs were extractable from kidney, liver, and fat and 64 100% of the TRRs were identified/ characterized in the three matrices. Dicamba per se, accounting for 63.28 92.82% of the TRR, was detected in kidney, liver, and fat. The metabolite DCSA was a major metabolite in kidney ( 10.55% TRR; 0.0057 ppm) and liver ( 11.77% TRR; 0.0017 ppm) and only a minor component in fat ( 1.23% TRR; 0.0001 ppm). An unknown, accounting for < 10% of the TRR was detected in liver. A trace ( 0.006% TRR) of 5 OH dicamba ( a plant dicamba metabolite) was detected in urine. Dicamba metabolism in ruminants is proposed by the registrant to proceed via formation of DCSA or 5 OH dicamba.

In its review, HED noted that the 14C residues in goat milk and muscle were not characterized/ identified, and the animals were dosed at only about 6 ppm. The registrant stated that 14C residues from milk and muscle were not characterized because of low total radioactivity in the samples. HED concludes that in this case, characterization and identification of 14Cresidues in milk and muscle is not critical because residues would be expected to be qualitatively similar to those found in fat, kidney, and liver. In addition, HED notes that the registrants have committed to conducting a ruminant feeding study at a feeding level of 1,000 ppm. The residue to be regulated consists of dicamba and DCSA as currently stated in the tolerance expression. Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 30 of 94 The initial study review had required that samples from these animal metabolism studies must be analyzed using GLC/ EC method AM 0685 to ensure that these compounds can be adequately recovered. Method AM 0685 has been successfully validated in milk, muscle, liver, kidney, and fat in an Agency laboratory ( Dicamba SRR, 6/ 30/ 89). In a follow up submission ( No MRID No.; DP Barcode D226526, 6/ 24/ 96, D. Miller), the registrant has responded that study reports have now been submitted relating to new method validation ( MRID 43461701) and confirmation of residues using the enforcement analytical method ( MRID 43554205). The 6/ 24/ 96 memo stated that these studies are presently in house awaiting review.

Poultry: In a poultry metabolism study ( MRID 43245202), [ 14C] dicamba was administered orally via capsule once daily for four consecutive days to five laying hens at a dose equivalent to 10 ppm in the diet. An additional three hens were orally dosed at 500 ppm. Only the analyses of the hens dosed at 10 ppm were presented. The 10 ppm dose is  1.9x the estimated maximum theoretical dietary exposure of 5.2 ppm ( see Table 6). The test substance had a radiochemical purity of 99% and a specific activity of 9.21 mCi/ mmol. Two additional hens served as controls. Eggs were collected twice daily. Within 24 hours following the final dose, the test animals were sacrificed and liver, muscle, and fat samples were collected. Samples were stored frozen ( 20 ° C) until analysis. All initial analyses were performed within 6 months of sample collection.

TRRs, expressed as dicamba equivalents, in samples taken from the treated hens were: 0.0014 0.004 ppm in egg yolk; 0.0018 0.0037 ppm in egg white; 0.0029 ppm in liver; 0.0003 ppm in breast muscle; 0.0005 ppm in leg muscle; and 0.0002 ppm in fat. The maximum residues were found in egg whites and egg yolks ( 0.004 ppm). Although TRRs were < 0.01 ppm for all matrices, residue characterization was conducted on liver and eggs. Radioactive residues in these matrices were extracted using organic solvents, and the nonextractable residues were acid hydrolyzed to release bound residues. The extractable residues were analyzed by TLC, and the identity of metabolites was confirmed by HPLC.

The results show that virtually 100% of the TRRs from liver and egg were extractable, and 95 97% of the TRRs were identified/ characterized in the two matrices. Dicamba per se accounted for 61.16% and 95.25% of the TRR in liver and eggs, respectively. The metabolite 2A36DCP was detected in liver ( 35.76% TRR;, 0.001 ppm) but not in eggs. The metabolites DCSA and 5 OH dicamba were not detected in liver or eggs but were detected in excreta and together accounted for < 3% of the TRR. Dicamba metabolism in poultry is proposed by the registrant to proceed via formation of DCSA subsequently followed by formation of 2A36DCP.

860.1340 Residue Analytical Methods Plant commodities The Pesticide Analytical Manual ( PAM) Vol. II lists Method I ( AM 0268A), a GC method with electron capture detection ( GC/ ECD) for the enforcement of dicamba tolerances for plant commodities. Using this method, residues of dicamba and its metabolites are extracted from crop commodities with sulfuric acid ether mixture, and the extract is passed through a buffered Celite column. Residues of dicamba and its 5 hydroxy metabolite are determined by GC/ ECD by Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 31 of 94 comparing the chromatograms with calibration curves made with methyl 2 methoxy 3, 6 dichlorobenzoate and methyl 2,5 dimethoxy 3, 6 dichlorobenzoate as standards. Residues of 3,5 dichloro o anisic acid are also determined by GC/ ECD by comparing the chromatograms with a calibration curve made with methyl 2 methoxy 3, 5 dichlorobenzoate as the standard. Method I was validated by Agency chemists on corn and sorghum commodities as matrices. The sensitivity of the method is listed at 0.05 ppm.

An improved plant enforcement method ( GC/ ECD) has resulted from the requirements of the 6/ 30/ 89 Residue Chemistry Chapter of the Dicamba ( SRR). The Chapter requested that Method AM 0691A or B, both of which were modifications to Method I of PAM Vol. II ( AM 0268A), be subjected to an independent laboratory validation ( ILV) because the method procedures included an acid hydrolysis step which increased the extraction efficiency of dicamba residues from various commodities. Method AM 0691B 0593 2 ( MRID 42883201) underwent successful ILV ( DP Barcode D194776, 12/ 14/ 93, D. Miller) and EPA method validation ( DP Barcode D232478, 1/ 21/ 97, J Stokes). In principle, Method AM 0691B has not changed over years. In brief, samples are treated with 1 N HCl and hydrolyzed for 1.5 hours in a 95 ° C water bath. The hydrolysate is adjusted to pH $ 8 with a 50 mL aliquot removed for analysis, then acidified to pH < 1, and extracted twice with diethyl ether. The combined ether extracts are concentrated and then methylated with diazomethane. Cleanup is by silica gel columns. Determination of the methylated residues is by capillary 63NiEC GC. Some of the minor changes that occurred in this method pertain to the extraction step ( no extraction with 80% ethanol in 1 N HCl), changes in the GC columns, and the addition of a GC MSD confirmatory step. [ Note: The use of diazomethane for enforcement methods is being discouraged by the Agency wherever an alternative is feasible. The registrant has shown elsewhere ( DEB memo 3/ 27/ 90, F. Griffith; DEB No. 6712, 7/ 26/ 90, S. Funk) that neither N, O bis( trimethylsilyl) trifluoroacetamide ( BSTFA) nor BF 3 / CH 3 OH will derivatize dicamba. Therefore, the continued use of diazomethane is necessitated.]

Pending a re write of the method to incorporate suggested changes/ corrections made by Agency chemists from ACL, the method will be forwarded to FDA for publication in PAM Vol. II as an addition to the entries of available enforcement methods for dicamba. It is noted that this method was recently superceded by method AM 0691B 0297 4 ( MRID 44394102), which consists of a more detailed step by step description of the procedures, GC MS confirmatory tests, and additional recovery data. The LOQ for dicamba and 5 OH dicamba is 0.02 ppm.

The data collection method, used for the analysis of samples collected from field and processing studies intended to replace Craven data, was AM 0691B. In all cases, the concurrent method recoveries were well within the acceptable range of 70 120%. However, in conjunction with PP# 4F3041 ( DP Barcode D228703, 7/ 16/ 98, S. Chun), additional method validation data using Method AM 0691B 0297 4 were requested for barley grain and straw at fortification levels of 6 and 15 ppm, respectively, and for wheat straw at 30 ppm because the maximum residues obtained from the respective field trials were not validated at these fortification levels.

The data collection method, used for the analysis of samples, collected from soybean field and processing studies, was the capillary GC EC residue analytical Method AM 0941 1094 0. The extraction steps of Method AM 0941 1094 0 and Method AM 0691B 0297 4 are essentially Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 32 of 94 identical. HED's PIRAT has previously determined that adequate validation data for Method AM 0941 1094 0 are available and, therefore, will not require additional ILV or PMV for this method. The registrant has committed to performing additional residue validation for soybean seeds at a fortification level of 10 ppm using method AM 0941 1094 0 in order validate the results of the soybean field trials.

Animal commodities The Pesticide Analytical Manual ( PAM) Vol. II lists Method II, a GC/ ECD method which is identical to Method I, for the enforcement of dicamba animal tolerances. The sensitivity of the method is listed at 0.01 ppm. Based on the results of animal metabolism study, which showed that acid hydrolysis can additionally extract up to 30% of TRR in goat liver, HED is requiring the registrants to revise/ improve Method II to include an acid hydrolysis step and submit additional validation data for animal matrices using the improved method. Method II should also be rewritten specifically for the analysis of the parent dicamba and its metabolite 3,6 dichloro 2 hydroxybenzoic acid metabolite in animal matrices.

860.1360 Multiresidue Methods According to FDA's PAM Volume I, Appendix II, dicamba is completely recovered using Section 402 E2 of Protocol B but is only partially recovered using Section 402 E1 of Protocol B. There are no multiresidue methods recovery data for the dicamba metabolites of concern ( 5 OH dicamba and DCSA), and these data are required. To fulfill this requirement, the registrants are required to follow the directions for the protocols found in PAM Vol. I, Appendix II under paragraph ( d)( 1) of OPPTS 860.1360 GLN, starting with the decision tree for multiresidue methods testing and the accompanying guidance found in the suggestions for producing quality data.

860.1380 Storage Stability MRID 43245204 ( Sugarcane ( DP Barcodes D204488, D204809, and D209229; 7/ 14/ 97; L. Cheng) MRID 43245205 ( Sorghum) ( DP Barcodes D204488, D204809, and D209229; 7/ 14/ 97; L. Cheng) MRID 43245206 ( Asparagus) ( DP Barcodes D204488, D204809, and D209229; 7/ 14/ 97; L. Cheng) MRID 43274501 ( Wheat) ( DP Barcodes D204488, D204809, and D209229; 7/ 14/ 97; L. Cheng) MRID 43370701 ( Grass forage and hay) ( DP Barcode D207649, 3/ 11/ 96, L. Cheng) MRID 43866601 ( Corn) ( DP Barcode D228703, 7/ 16/ 98, S. Chun) MRID 43814102 ( Soybean) ( DP Barcodes D223283, ...; 7/ 29/ 96; S. Knizner, W. Dykstra, and C. Lewis)

Plant commodities The Dicamba ( SRR) Registration Standard dated 6/ 30/ 89 noted disparity in the storage stability data from a few earlier study submissions and requested additional data. New storage stability data have subsequently been submitted, and many of these storage stability data were included in the submissions for field and processing studies to replace Craven data. The new data have all been reviewed and deemed adequate to satisfy reregistration requirements except for the requirement to submit data for sugarcane molasses. HED is requiring storage stability data for Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 33 of 94 sugarcane molasses to validate the interval and conditions ( 64 days, < 1 ° C) of samples from the submitted sugarcane processing study ( MRID 43245204).

There are now adequate storage stability data for various representative crop commodities. These data indicate that residues of dicamba, 5 OH dicamba and DCSA are reasonably stable under frozen storage conditions at the maximum intervals tested. The data summarized below fulfill the reregistration requirements for storage stability data on plant commodities except for sugarcane molasses. For the purpose of tolerance reassessment, the maximum residues observed in the field and processing studies need not be adjusted or corrected for any decline in residues.

A storage stability study for field corn matrices ( MRID 43866601) is available. In this study, residues of dicamba and 5 OH dicamba were found to be stable under frozen storage conditions in/ on field corn forage, silage, grain, and fodder for up to 3 and 2 years, respectively. These data validate the storage conditions and intervals of samples collected from the most recent field corn trials. The HED review of these corn storage stability data concluded that the data may be translated to other cereal grains. The storage conditions and intervals of samples collected from residue field studies of various cereal grain crops follow. Wheat grain samples reviewed in conjunction with PP# 4F3041 were stored frozen for 35 197 days (~ 1 7 months), and wheat straw samples were stored frozen for 51 220 days (~ 2 7 months). Barley forage samples were stored frozen for 29 149 days (~ 1 5 months), barley grain samples were stored frozen for 21 147 days (~ 1 5 months), barley hay samples were stored frozen for 40 160 days (~ 1 5 months), and barley straw samples were stored frozen for 27 177 days (~ 1 6 months).

A storage stability study for soybean matrices ( MRID 43814102) has been submitted/ reviewed. The results show that residues of dicamba and DCSA are stable under frozen storage conditions in/ on soybean forage for up to 4 months and in refined oil for up to 3 months. Samples of soybeans and processed soybean fractions, collected from the field and processing studies, were stored frozen from 4 10 months prior to residue analysis.

In conjunction with the wheat field trials ( MRID 43274501), the registrant conducted a storage stability study using wheat forage and hay. The data indicate that residues of dicamba and its 5 OH metabolite are stable in/ on frozen wheat forage and hay for up to 258 and 283 days, respectively. Wheat forage and hay samples from the field study were stored at < 17 ° C for 4 357 days prior to analysis; however, only 10 of the  350 samples had a storage interval of > 200 days.

In conjunction with the grass field trials ( MRID 43370701), the registrant submitted data depicting the frozen storage stability of dicamba and its 5 OH metabolite in/ on grass forage and hay. These data indicate that residues of dicamba and 5 OH dicamba are stable in/ on frozen grass forage and hay for up to 314 and 320 days, respectively ( 10 months). Samples collected from this study were stored frozen for up to 13 months prior to residue analysis.

In conjunction with the sorghum processing study ( MRID 43245205), the registrant submitted data depicting the frozen storage stability of dicamba and its 5 OH metabolite in/ on sorghum grain. These data indicate that residues of dicamba and 5 OH dicamba are stable in/ on frozen Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 34 of 94 sorghum grain for up to 5 months and are adequate to support the storage interval and conditions of the grain and grain dust samples ( up to 5 months, < 17 ° C).

In conjunction with the asparagus field trial ( MRID 43245206), the registrant submitted supporting storage stability data which indicate that residues of dicamba and DCSA are stable in/ on asparagus for up to 104 days of frozen (< 12 ° C) storage and that residues of 5 OH dicamba are stable for up to 119 days of frozen (< 12 ° C) storage. Samples in the asparagus field trials ( MRIDs 43245206 and 43245803) were stored frozen at < 12 ° C for up to 95 days prior to analysis.

In conjunction with the sugarcane processing study ( MRID 43245204), the registrant submitted supporting storage stability data which indicate that residues of dicamba and its hydroxy metabolite are stable in the refined white sugar of sugarcane stored frozen up to 60 days at < 1 ° C. Confirmatory storage stability data reflecting storage interval of 64 days are required for sugarcane molasses.

Animal commodities There are no available storage stability data for animal commodities. There is a ruminant feeding study currently under review. If the samples were stored frozen and analyzed promptly ( within a month), then supporting storage stability data would not be required. Otherwise storage stability studies of the parent dicamba and its 3,6 dichloro 2 hydroxybenzoic acid metabolite in milk and ruminant tissues would be required.

860.1400 Water, Fish, and Irrigated Crops There are no registered or proposed uses that are relevant to this guideline topic.

860.1460 Food Handling There are no registered or proposed uses that are relevant to this guideline topic.

860.1480 Meat, Milk, Poultry, and Eggs Maximum theoretical dietary burden ( MTDB)

There are several livestock feed items associated with the crops which are being supported for reregistration. Following tolerance reassessment, the MTDBs of dicamba have been calculated as follows: 82 ppm for beef cattle; 482 ppm dairy cattle; 5.65ppm swine; and 5.2 ppm for poultry; see Tables 6 and 7. The feed items which contribute significantly to the dietary burdens for ruminants include grass forage/ hay, aspirated grain fractions, and cereal grains. Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 35 of 94 Table 6. Calculation of Maximum Dietary Burdens of Dicamba to Livestock.

Feedstuff % Dry Matter 1 % Diet 1 Reassessed Tolerance ( ppm) Dietary Contribution ( ppm) 2 Beef Cattle Grass hay 88 20 250 56.82 Aspirated grain fractions 85 5 1000 58.82 Corn grain 88 60 0.1 0.07 Soybean Meal 82 15 10 1.83 TOTAL BURDEN  100  117.54 Dairy Cattle Grass forage 25 30 400 480.00 Undelinted Cotton Seed 88 10 5 0.57 Corn grain 88 50 0.1 0.06 Wheat grain 89 20 2.0 0.45 Soybean Meal 82 10 10 1.22 TOTAL BURDEN  100  481.84 Swine Sorghum grain 86 80 4.0 3.82 Soybean Meal 82 15 10 1.83 TOTAL BURDEN  100  5.65 Poultry Soybean seed 89 20 10 2.0 Sorghum grain 86 80 4.0 3.2 TOTAL BURDEN  100  5.2 1 Table 1 ( OPPTS Guideline 860.1000). 2 Contribution = ([ tolerance /% DM] x % diet) for beef and dairy cattle; contribution = ( tolerance x % diet) for poultry and swine.

Ruminants Established tolerance( s): Tolerances have been established under 40 CFR § 180.227 ( a)( 2) for the combined residues of dicamba and its DCSA metabolite in the: ( i) fat, meat, and meat byproducts of cattle, goat, hog, horse, and sheep at 0.2 ppm; ( ii) kidney and liver of cattle, goat, hog, horse, and sheep at 1.5 ppm; and ( iii) milk at 0.3 ppm.

Conclusions: The available ruminant feeding study ( MRID 00079742), which was discussed in PP# 3F2794 and re summarized in the HED review ( DP Barcodes D220430,... 5/ 2/ 96, F. Griffith) was conducted at 400 ppm. A new bovine feeding study was required. HED notes that the registrant, BASF, has committed ( DP Barcode D228703, 7/ 16/ 98, S. Chun) to conduct a bovine feeding study at a feeding level of 1000 ppm. The study has been submitted ( MRID 44891303) and is currently under review. A cursory review of the study indicates that modification of the tolerances are required at levels ranging from 0.2 ppm for fat to 25 ppm for kidney. Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 36 of 94 Poultry Established tolerance( s): No tolerances are established for the combined residues of dicamba and its DCSA metabolite in poultry eggs and meat.

Conclusions: A poultry feeding study with dicamba is not required based on the results of the submitted poultry metabolism study ( MRID 43245202). In this study, the TRR levels in eggs, liver, muscle, and fat were all < 0.004 ppm following dosing at 10 ppm ( 1.9x the maximum dietary burden of 5.2 ppm) in the diet for four consecutive days. Residues in eggs plateaued after the first day of dosing ( i. e., there was no accumulation with increasing days of dosing). HED does not anticipate the occurrence of quantifiable residues of dicamba or DCSA in poultry eggs and meat as a result of treating crops with poultry feed items at the maximum use patterns. Therefore, HED concludes that tolerances are not needed in poultry eggs and meat at this time but may be required if additional uses are registered in the future. A poultry feeding study ( MRID 00148127) with dicamba, reflecting feeding rates equivalent to 2, 6, and 20 ppm in the diet, is available; these data were summarized in PP# 3F2794 ( 8/ 15/ 85 memo, M. Firestone).

860.1500 Crop Field Trials Residue studies that were generated by Craven Laboratories had been identified by HED, and a Data Call In Notice was issued on 02/ 94 requesting end use producer( s) of dicamba to conduct new field trials on barley, corn ( field), sorghum, soybean, sugarcane, and wheat ( D204754, 7/ 12/ 94, S. Funk). Several residue chemistry studies have been submitted and reviewed in response to the Dicamba DCI Notice. These Craven replacement data along with those data for other crops which will be supported for reregistration were re evaluated in this Residue Chemistry Chapter.

Legume Vegetables ( Crop Group 6)

Soybean seed MRID 43814101 ( DP Barcodes D223283, ... 7/ 29/ 96, S. Knizner, W. Dykstra, and C. Lewis) MRID 44089307 ( DP Barcode D228703, 7/ 16/ 98, S. Chun)

Established tolerance( s): A tolerance of 10 ppm has been established for the combined residues of dicamba and its two metabolites ( 5 OH dicamba and DCSA) in/ on soybean seed [ 40 CFR § 180.227 ( a)( 3)].

Uses to be supported: According to the Dicamba Master Use Profile ( see Table 4), use of dicamba and its salts on soybeans will be supported at a maximum seasonal rate of 2.0 lb ae/ A. In conjunction with PP# s 6F4604 and 4F3041 ( DP Barcode D249098, 10/ 13/ 98, W. Donovan), the registrant has submitted a revised Section B specifying a 7 day PHI for soybeans.

Conclusions: There are adequate Craven replacement studies depicting magnitude of the regulated residues in/ on soybean seed. Data from these submissions show that the highest total Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 37 of 94 residues ( dicamba + DCSA + 5 OH dicamba) were 3.74 ppm ( MRID 43814101) and 8.13 ppm ( MRID 44089307) in/ on samples of soybean seed harvested 6 8 days following the last of a treatment schedule which includes a preplant application at 0.5 lb ae/ A followed by a preharvest broadcast application at 2.0 lb ae/ A for a total of 2.5 lb ae/ A ( 1.25x the maximum rate listed in the Dicamba Master Use Profile). The available data indicate that the established tolerance of 10 ppm for soybean seed will not be exceeded when representative salt formulations of dicamba are applied at a slightly exaggerated total rate of 2.5 lb ae/ A.

Discussion of data: The study reported in MRID 43814101 include data from 17 soybean trials conducted during the 1994 growing season in AR, GA, IL( 2) , IN( 2), IA( 2), LA, MN( 2), MS, MO( 2), NE, OH, and TN. The number and locations of soybean trials from this study along with those conducted in MRID 44089307 are adequate to satisfy GLN 860.1500 with regard to geographic representation of data. Two types of treatment patterns were evaluated using the DMA salt formulation of dicamba: ( i) a single preplant ( 14 days prior to planting) broadcast application at 0.5 lb ae/ A ( 0.25x); and ( ii) preplant treatment at 0.5 lb ae/ A plus preharvest broadcast application at 2.0 lb ae/ A for a total of 2.5 lb ae/ A ( 1.25x). In addition, four side byside trials were conducted in IA, IL, IN, and MN with the DGA, DMA, and Na salt formulations of dicamba at the same application rates and harvest intervals; soybeans seeds were harvested 6 8 days following posttreatment. Injury ( e. g., delayed emergence, delayed opening of cotyledons, and reduced stand) was observed in the treated plots after the preplant treatment.

The harvested soybean seed samples were analyzed using GC Method No. AM 0941 1094 0 with a limit of detection of 0.01 ppm for each residue in all matrices. In this method, residues of dicamba and DCSA were quantitated by GC using a Ni electron capture detector ( ECD) whereas residues of 5 OH dicamba were quantitated separately by GC/ ECD. This method was validated at fortification range of 0.01 0.5 ppm. The method recoveries were well within the acceptable range. Soybean seed samples were stored frozen for a maximum interval of 220 days ( 7 months) prior to residue analysis. There are adequate storage stability data to support this interval.

The results show that following a single preplant broadcast treatment ( 14 days prior to planting) of the DMA salt of dicamba at 0.5 lb ae/ A ( 0.25x), residues of dicamba, DCSA, and 5 OHdicamba were each < 0.01 ppm in/ on soybean seeds. Following preplant plus preharvest treatments for a total of 2.5 lb ae/ A ( 1.25x), individual residues in/ on soybean seed samples harvested at a 6 8 day PHI were 0.072 3.301 ppm for dicamba per se, < 0.01 0.115 ppm for DCSA, and < 0.01 0.357 ppm for 5 OH dicamba. The HAFT combined residues in/ on treated soybean seed from this study was 3.6 ppm. In side by side trials using the DMA, DGA, and Na salts of dicamba, residue levels did not vary according to the formulation used.

MRID 44089307: Six soybean field trials were conducted in IA, IN, IL( 2), MO, and NC using the DMA salt formulation of dicamba. Two types of treatments were used. Treatment A ( PRPR1) consisted of a preplant broadcast application of 0.5 lb ae/ A ( 0.25x), made to the soil surface 14 days before planting soybean. Treatment B ( POPO1) consisted of Treatment A plus a preharvest broadcast application of 2.0 lb ae/ A for a total of 2.5 lb ae/ A ( 1.25x), made 7 days before normal harvest. Only grain samples were collected from Treatment B. Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 38 of 94 Samples were analyzed for dicamba, its 5 OH dicamba metabolite, and its DCSA metabolite using a GC/ ECD method ( AM 0941 1094 0). The LOQ for this method is 0.02 ppm. The method was validated over a range of 0.02 1.0 ppm for soybean commodities. The overall average corrected recovery for all matrices ( hay, grain, and forage) was 98% ± 13 ( n= 17) for dicamba, 93% ± 18 ( n= 16) for DCSA, and 90% ± 11 ( n= 15) for 5 OH dicamba. HED review of this study noted that residues in soybean seed were found well above the range of the method validation, and therefore, requested additional method validation at a spike level of up to 10 ppm in soybean seed. Total storage interval, between harvest and analysis, for all samples was 31 104 days (~ 1 3 months). This interval is supported by adequate storage stability data.

The results show that following preplant broadcast application at 0.25x, residues of dicamba, DCSA, and 5 OH dicamba were < 0.01 ppm each in/ on soybean seed. Total residues ( dicamba + DCSA + 5 OH dicamba) in/ on soybean seed from Treatment A were calculated at < 0.015 ppm. Following a combination of preplant + preharvest applications at 1.25x, the ranges of individual residues in/ on soybean seed harvested at a 7 day PHI were: 0.027 8.1 ppm for dicamba, < 0.01 0.033 ppm for DCSA, and < 0.01 0.011ppm for 5 OH dicamba. Total residues ( dicamba + DCSA + 5 OH dicamba) in/ on soybean seed which received preplant plus preharvest treatments were 0.037 8.13 ppm. The HAFT combined residues in/ on treated soybean seed from this study was 7.44 ppm.

Foliage of Legume Vegetables ( Crop Group 7)

Soybean forage and hay MRID 43814101 ( DP Barcodes D223283, ... 7/ 29/ 96, S. Knizner, W. Dykstra, and C. Lewis) MRID 44089307 ( DP Barcode D228703, 7/ 16/ 98, S. Chun)

Established tolerance( s): No dicamba tolerances are currently established on soybean forage and hay.

Uses to be supported: According to the Dicamba Master Use Profile ( see Table 4), use of dicamba and its salts on soybeans will be supported at a maximum seasonal rate of 2.0 lb ae/ A.

Conclusions: There are Craven replacement studies ( MRIDs 43814101 and 44089307) depicting magnitude of the regulated residues in/ on soybean forage and hay. Data from MRID 43814101 show that following one preplant application of the DMA salt formulation of dicamba at 0.5 lb ae/ A ( 0.25x the maximum rate listed in the Dicamba Master Use Profile), the total residues ( dicamba, DCSA, and 5 OH dicamba) ranged < 0.03< 0.097 ppm for soybean forage and < 0.03 < 0.04 ppm for soybean hay. In another submission ( MRID 44089307), it was reported that the total residues in/ on samples treated similarly were 0.015 0.062 ppm for soybean forage and < 0.015 ppm for soybean hay.

It is the current Agency policy to allow label restrictions on the feeding/ grazing of livestock animals on soybean forage and hay, thus, precluding the need for residue data and tolerances for these soybean commodities. HED defers to RD for verifying whether such restrictions exist on product labels. If such restrictions appear on the labels, then residue data and tolerances for Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 39 of 94 soybean forage and hay are not necessary. If no such restrictions appear on the labels, then the registrants are required to propose tolerances for soybean forage and hay at 0.1 ppm each. Concomitant with these tolerance proposals, the registrants are required to propose a maximum seasonal rate of 0.5 lb ae/ A for preplant application on soybean grown for forage and hay only.

Discussion of data: The study reported in MRID 43814101 include data from 17 soybean trials conducted during the 1994 growing season in AR, GA, IL( 2) , IN( 2), IA( 2), LA, MN( 2), MS, MO( 2), NE, OH, and TN. The number and locations of soybean trials from this study along with those conducted in MRID 44089307 are adequate to satisfy GLN 860.1500 with regard to geographic representation of data. Two types of treatment patterns were evaluated using the DMA salt formulation of dicamba: ( i) a single preplant ( 14 days prior to planting) broadcast application at 0.5 lb ae/ A ( 0.25x); and ( ii) preplant treatment at 0.5 lb ae/ A plus preharvest broadcast application at 2.0 lb ae/ A for a total of 2.5 lb ae/ A ( 1.25x). In addition, four side byside trials were conducted in IA, IL, IN, and MN with the DGA, DMA, and Na salt formulations of dicamba at the same application rates and harvest intervals. Soybean forage and hay were collected from plants receiving only preplant treatment. Only soybeans seeds were collected from plants which received both preplant and preharvest treatments. Samples were analyzed using GC Method No. AM 0941 1094 0 with a limit of detection of 0.01 ppm for each residue in all matrices. In this method, residues of dicamba and DCSA were quantitated by GC using a Ni ECD whereas residues of 5 OH dicamba were quantitated separately by GC/ ECD. This method was validated at fortification range of 0.01 0.5 ppm. The method recoveries were well within the acceptable range. Samples were stored frozen for maximum intervals of 175 316 days ( 6 10 months) for forage and 140 230 days ( 5 8 months) for hay prior to residue analysis. There are adequate storage stability data to support these intervals. The results show that following a single preplant broadcast treatment ( 14 days prior to planting) of the DMA salt of dicamba at 0.5 lb ae/ A ( 0.25x), the total residues ( dicamba, DCSA, and 5 OH dicamba) ranged < 0.03< 0.097 ppm for soybean forage and < 0.03< 0.04 ppm for soybean hay. In side by side trials using the DMA, DGA, and Na salts of dicamba, residue levels did not vary according to the formulation used.

MRID 44089307: Six soybean field trials were conducted in IA, IN, IL( 2), MO, and NC using the DMA salt formulation of dicamba. Two types of treatments were used. Treatment A ( PRPR1) consisted of a preplant broadcast application of 0.5 lb ae/ A ( 0.25x), made to the soil surface 14 days before planting soybean. Treatment B ( POPO1) consisted of Treatment A plus a preharvest broadcast application of 2.0 lb ae/ A for a total of 2.5 lb ae/ A ( 1.25x), made 7 days before normal harvest. Forage and hay samples were collected from Treatment A. Samples were analyzed for dicamba, its 5 OH dicamba metabolite, and its DCSA metabolite using a GC/ ECD method ( AM 0941 1094 0). The LOQ for this method is 0.02 ppm. The method was validated over a range of 0.02 1.0 ppm for soybean commodities. The overall average corrected recovery for all matrices ( hay, grain, and forage) was 98% ± 13 ( n= 17) for dicamba, 93% ± 18 ( n= 16) for DCSA, and 90% ± 11 ( n= 15) for 5 OH dicamba. Total storage interval, between harvest and analysis, for all samples was 31 104 days (~ 1 3 months). This interval is supported by adequate storage stability data. The results show that the total residues ( dicamba + DCSA + 5 OH dicamba) were 0.015 0.062 ppm in/ on soybean forage and < 0.015 ppm in/ on soybean hay samples following a preplant treatment at 0.5 lb ae/ A; the PHI was not specified. Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 40 of 94 Cereal Grains ( Crop Group 15)

The adequacy of available residue data for the individual cereal grains, which are being supported for reregistration, are detailed below.

Barley grain MRID 44089304 ( DP Barcode D228703, 7/ 16/ 98, S. Chun)

Established tolerance( s): A tolerance of 6.0 ppm has been established for the combined residues of dicamba and its metabolite ( 5 OH dicamba) in/ on barley grain [ 40 CFR § 180.227 ( a)( 1)].

Uses to be supported: According to the Dicamba Master Use Profile ( see Table 4), the DMA, Na, DGA, and IPA salts will be supported on barley at a maximum single application rate of 0.25 lb ae/ A and a maximum yearly rate of 0.38 lb ae/ A. In conjunction with PP# s 6F4604 and 4F3041 ( DP Barcode D249098, 10/ 13/ 98, W. Donovan), the registrant has submitted a revised Section B specifying a 7 day PHI for barley.

Conclusions: There are Craven replacement data ( MRID 44089304) depicting residues of dicamba and 5 OH dicamba in/ on barley grain at application rates of 0.125 or 0.375 lb ae/ A. The combined residues of dicamba and 5 OH dicamba ranged 0.021 1.203 ppm in/ on samples of barley grain harvested 7 days following one broadcast application made to the crop prior to first joint stage using representative dicamba salt formulations at 0.125 lb ae/ A ( 1x). Other data points indicate that the combined residues were 0.671 5.063 ppm in/ on grain samples harvested 7 days following the last of two treatments ( with the first made prior to joint stage followed by a preharvest treatment) for a total of 0.375 lb ae/ A ( 1x). The existing tolerance of 6.0 ppm for barley grain is adequate and no additional data are required.

Discussion of data: The submission for MRID 44089304 depicts magnitude of the residues of dicamba and 5 OH dicamba in/ on barley grain. Eleven field trials were conducted in CA, ID, MN, MT, ND( 2), OR, PA, SD( 2), and UT. A field trial was also conducted in WY but no samples were collected from this trial site. Geographic representation of data is adequate since the number and location of barley trials is in accordance with Table 1 of GLN 860.1500. The barley field trials were conducted using the following salt formulations of dicamba: DMA, DGA, and Na.

Two types of treatments were used. Treatment A ( POPO1) consisted of one broadcast application at 0.125 lb ae/ A, made to the crop immediately prior to first joint stage. Treatment B ( POPO2) consisted of Treatment A plus a preharvest broadcast application at 0.25 lb ae/ A, made 7 days before normal harvest. The DMA salt formulation of dicamba was applied in five trial locations. Side by side trials with DMA, DGA, and Na salt formulations of dicamba were conducted at four different trial locations. Samples were analyzed for dicamba and 5 OH dicamba using a GC/ ECD method ( Sandoz Method AM 0691B 0593 3) with an LOQ of 0.01 ppm. The adequacy of the method for data collection was validated by fortifying grain control samples with dicamba and 5 OH dicamba at 0.01 1.0 ppm. The average method recoveries for the field trials were acceptable (> 70%) for all barley commodities. However, the HED review noted that the Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 41 of 94 method was not validated over an acceptable range since residue levels in barley grain were found well above the ranges of the method validation. The HED review, thus, requested additional method validation at a spike level of up to 6.0 ppm for barley grain. Barley grain samples were stored frozen for 21 147 days (~ 1 5 months) prior to residue analysis. There are adequate storage stability data available for field corn matrices which may be translated to barley grain.

The results indicate that the total residues ( dicamba + 5 OH dicamba) in/ on all treated barley grain samples ranged 0.021 1.203 ppm for Treatment A ( 1x) and 0.671 5.063 ppm for Treatment B ( 1x). Statistical analysis performed by the registrant suggested that there was no significant difference in the magnitude of the residue samples based on formulation.

Corn, field, grain MRID 44089303 ( DP Barcode D228703, 7/ 16/ 98, S. Chun)

Established tolerance( s): A tolerance of 0.5 ppm has been established for the combined residues of dicamba and its metabolite ( 5 OH dicamba) in/ on " corn, grain" [ 40 CFR § 180.227 ( a)( 1)].

Uses to be supported: According to the Dicamba Master Use Profile ( see Table 4), the DMA, Na, DGA, and K salts of dicamba will be supported on field corn at a maximum single application rate of 0.5 lb ae/ A and a maximum yearly rate of 0.75 lb ae/ A.

Conclusions: There are Craven replacement data ( MRID 44089303) depicting residues of dicamba and 5 OH dicamba in/ on field corn grain. These data represent not only the application specifically listed for corn, but also the use on fallow agricultural soils at 2 lb ae/ A for a total rate of 2.75 lb ae/ A. The combined residues of dicamba and 5 OH dicamba ranged from < 0.01 to 0.015 ppm in/ on field corn grain samples harvested 69 123 days following the last of three sequential treatments ( 2.0 lb ae/ A + 0.5 lb ae/ A + 0.25 lb ae/ A) of representative dicamba salt formulations for a total of 2.75 lb ae/ A. No residues of dicamba per se were detected in/ on any of the treated grain samples from any of the trial locations. Residues of 5 OH dicamba ranged from < 0.01 to 0.015 ppm. The data support reduction of the tolerance to 0.1 ppm.

Discussion of data: The submission for MRID 44089303 includes data from a total of 20 field corn trials conducted between 1994 1995 in 16 states: IA( 2), IL( 2), IN, KS, KY, MN( 2), MI, MO, NE( 2), NC, ND, OH, OK, PA, SD and WI. These states cover EPA regions I ( 1), II ( 1), V ( 17), and VI ( 1). Geographic representation of data is adequate since the number and location of field corn trials is in accordance with Tables 1 and 5 of GLN 860.1500. The DMA salt formulation was applied in 12 trial locations. Side by side trials with the DMA, DGA, and Na salt formulations of dicamba were conducted at 8 trial locations to compare the residues found from use of the different salt formulations.

Three broadcast applications of dicamba were used on each treated plot at each site. The first application at 2.0 lb ae/ A was made to crop stubble, fallow or bare ground in the fall of 1994 prior to ground freeze, with subsequent planting of field corn in the spring of 1995. The second application at 0.5 lb ae/ A was made in the spring to 8 inch tall field corn. The last application at Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 42 of 94 0.25 lb ae/ A was made in the spring or summer to 36 inch tall field corn. The total applied rate was 2.75 lb ae/ A ( 3.7x the maximum yearly rate listed in the Dicamba Master Use Profile). Samples of field corn grain were collected at a PHI range of 66 123 days.

Samples of field corn grain were analyzed for dicamba and 5 OH dicamba using a GC/ ECD method ( Sandoz Method AM 0691B 0593 3) with a limit of detection of 0.01 ppm. The adequacy of the method for data collection was validated by separately fortifying grain control samples with dicamba and 5 OH dicamba at the following levels: 0.010, 0.10, 0.50, and 1.0 ppm. Method recoveries were within the acceptable range. Information pertaining to sample storage intervals was not specified in the HED review. However, there are adequate storage stability data which indicate that dicamba and 5 OH dicamba residues are stable in/ on corn matrices under frozen storage conditions for up to 3 and 2 years, respectively.

The results indicate that the total residues ( dicamba + 5 OH dicamba) in/ on all treated grain samples ranged from < 0.01 to 0.015 ppm. No residues of dicamba were detected in any of the treated grain samples from any of the trial locations. Residues of 5 OH dicamba ranged from < 0.01 to 0.015 ppm. Analysis of Variance ( ANOVA) statistical analysis was performed on the data collected from the 8 locations where the DMA, DGA, and Na dicamba salt formulations were used. The results indicate that the difference in the magnitude of the residues observed in grain was influenced by the difference in the trial locations and not by the difference in the dicamba salt formulations.

Corn, pop, grain Established tolerance( s): A tolerance of 0.5 ppm has been established for the combined residues of dicamba and its metabolite ( 5 OH dicamba) in/ on " corn, grain" [ 40 CFR § 180.227 ( a)( 1)].

Uses to be supported: According to the Dicamba Master Use Profile ( see Table 4), the DMA, Na, DGA, and K salts of dicamba will be supported on pop corn at a maximum single application rate of 0.5 lb ae/ A and a maximum yearly rate of 0.75 lb ae/ A.

Conclusions: There are no residue data on pop corn grain reflecting the maximum rate of 0.75 lb ae/ A which is the maximum single/ yearly application rate the registrants wish to support for pop corn. HED will allow the translation of available data for field corn grain to pop corn grain since the Dicamba Master Use Profile indicates that the application rate of the two crops is identical. However, any label revision for field corn should also be made for pop corn.

Millet, proso, grain Established tolerance( s): A tolerance of 0.5 ppm has been established for the combined residues of dicamba and its metabolite ( 5 OH dicamba) in/ on proso millet grain [ 40 CFR § 180.227 ( a)( 1)].

Uses to be supported: According to the Dicamba Master Use Profile ( see Table 4), the DMA salt of dicamba will be supported on proso millet at a maximum single application rate of 0.125 lb ae/ A and a maximum yearly rate of 0.125 lb ae/ A. Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 43 of 94 Conclusions: The current RAC tolerance level of 0.5 ppm was established through an IR 4 petition ( PP# 9E2166) based on limited residue data generated on proso millet from two field trials conducted in NE at 0.125 lb ae/ A ( 0.125x). Consistent with the recommendation of Dicamba ( SRR) Registration Standard dated 6/ 30/ 89, HED will allow the translation of available data for wheat grain to proso millet grain since the Dicamba Master Use Profile indicates that the application rate for wheat is higher. Based on the wheat grain data, HED recommends that the tolerance be increased to 2.0 ppm.

Oat grain Established tolerance( s): A tolerance of 0.5 ppm has been established for the combined residues of dicamba and its metabolite ( 5 OH dicamba) in/ on oat grain [ 40 CFR § 180.227 ( a)( 1)].

Uses to be supported: According to the Dicamba Master Use Profile ( see Table 4), the DMA, Na, and DGA salts of dicamba will be supported on oats at a maximum single application rate of 0.125 lb ae/ A and a maximum yearly rate of 1.0 lb ae/ A.

Conclusions: There are no residue data on oat grain reflecting the maximum rate of 1.0 lb ae/ A which is the maximum single/ yearly application rate the registrants wish to support for oats. The current RAC tolerance level of 0.5 ppm was established through PP# 8F0666 based on limited data generated on spring seeded oats from trials conducted in VA at application rates of 0.125 to 0.25 lb ae/ A ( 0.125x to 0.25x). Consistent with the recommendation of Dicamba ( SRR) Registration Standard dated 6/ 30/ 89, HED will allow the translation of available and requested data for wheat grain to oat grain since the Dicamba Master Use Profile indicates that the application rate of the two crops is identical. Any label revision for wheat should also be made for oats. Concurrently, any adjustment to the wheat grain tolerance should also be applied as necessary to the oat grain tolerance.

Rye grain Established tolerance( s): No dicamba tolerance has been established for rye grain.

Uses to be supported: According to the Dicamba Master Use Profile ( see Table 4), the DMA salt of dicamba will be supported on rye at a maximum single application rate of 0.5 lb ae/ A and a maximum yearly rate of 1.0 lb ae/ A.

Conclusions: There are no available residue data on rye grain. HED will allow the translation of available and requested data for wheat grain to rye grain since the Dicamba Master Use Profile indicates that the yearly application rate of the two crops is identical. Any label revision for wheat should also be made for rye. Concurrently, any adjustment to the wheat grain tolerance should also be applied as necessary to the rye grain tolerance that needs to be established. Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 44 of 94 Sorghum grain MRID 43245203 ( DP Barcodes D204488, D204809, and D209229; 7/ 14/ 97; L. Cheng) MRID 44089306 ( DP Barcodes D304019, D306687 D306690; in review, C. Olinger)

Established tolerance( s): A tolerance of 3.0 ppm has been established for the combined residues of dicamba and its metabolite ( 5 OH dicamba) in/ on sorghum grain [ 40 CFR § 180.227 ( a)( 1)].

Uses to be supported: According to the Dicamba Master Use Profile ( see Table 4), all salts of dicamba will be supported on sorghum at a maximum single application rate of 0.2748 lb ae/ A and a maximum yearly rate of 0.5 lb ae/ A.

Conclusions: The registrant has submitted Craven replacement data depicting residues of dicamba and 5 OH dicamba in/ on sorghum grain. These data have been reviewed and deemed adequate to satisfy reregistration requirements pending label revisions and tolerance adjustment. The submitted data show that the maximum combined residues of dicamba and its 5 OH metabolite were 2.73 ppm ( MRID 43245203) and 3.164 ppm ( MRID 44089306) in/ on sorghum grain harvested 30 42 days following the last of a treatment schedule which includes one post directed application made under the crop canopy at 0.25 lb ae/ A followed by a second broadcast application made at soft dough stage at 0.25 lb ae/ A for a total rate of 0.5 lb ae/ A ( 1x the maximum rate listed in the Dicamba Master Use Profile). These data suggest that the established tolerance for sorghum grain may be too low. Based on the reviewed data, HED is recommending tolerance level of 4.0 ppm for sorghum grain concomitant with label revision to specify a 30 day PHI.

Discussion of data: The submission for MRID 43245203 contain data depicting residues of dicamba and its 5 OH metabolite in/ on sorghum grain. A total of 40 field trials were conducted in KS( 8), MO( 8), NE( 8), OK( 8), and TX( 8) using four salt formulations of dicamba: the Na, DGA, K, and DMA salts. Geographic representation of data is more than adequate when the trials conducted from this study along with those conducted from MRID 44089306 are considered. At each test site, one or two applications of each of the four dicamba formulations were made at 0.25 lb ae/ A/ application for total rates of 0.25 lb ae/ A ( 0.5x) and 0.5 lb ae/ A ( 1x). Applications were made in 19.6 21.5 GPA using ground equipment. The 0.5x plots were treated when the plants were 15" tall using a broadcast application sprayed directly under the canopy ( 20 109 PTI). The 1x plots received an additional application of 0.25 lb ae/ A when the crop was at the soft dough stage ( 30 42 PTI).

Sorghum grain samples were analyzed for residues of dicamba and 5 OH dicamba using a GC/ ECD method ( Method AM 0691B) with a limit of detection of 0.01 ppm for each analyte. The adequacy of the method for data collection was validated by fortifying untreated grain samples with dicamba and 5 OH dicamba at 0.01 0.1 ppm. Method recoveries were within the acceptable range. Samples were stored frozen at < 17 ° C for 28 160 days ( 1 5 months) prior to analysis. There are adequate storage stability data for sorghum grain to support sample storage conditions and intervals. Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 45 of 94 The results show that the combined residues of dicamba and its 5 OH metabolite were < 0.02 0.184 ppm in/ on 18 grain samples harvested 81 109 days following a single postemergence application at 0.25 lb ae/ A ( 0.5x). Following two applications for a seasonal total of 0.5 lb ae/ A ( 1x), the maximum combined residues were 2.73 ppm in/ on 20 grain samples collected at PHIs of 30 42 days.

MRID 44089306: A total of seven sorghum trials were conducted in Regions 2 ( NC; 1 trial), 4 ( LA; 1 trial), 5 ( IL and KS; 2 trials); 6 ( OK; 1 trial), 7 ( NE; 1 trial), and 8 ( TX; 1 trial) during the 1995 growing season. The DMA salt of dicamba was the test formulation used in all trials. At each field trial site, two separate plots were treated with either a single post directed spray application made under the crop canopy of 15 inch tall sorghum plants at a rate of 0.25 lb ae/ A ( 0.5x) or two applications ( one post directed application followed by a second broadcast application made at soft dough stage) at 0.25 lb ae/ A/ application, with a 44 to 65 day retreatment interval, for a total rate of 0.5 lb ae/ A ( 1x). Applications were made in 10 36 gal/ A of water using ground equipment. Sorghum grain was collected from 1x treated sites at PHIs of 30 to 34 days.

Samples were analyzed for residues of dicamba and its 5 OH metabolite using GC/ ECD method AM 0691B 0593 3 with a validated LOQ of 0.02 ppm for each analyte. The method is adequate for data collection based on acceptable concurrent method recovery data. The grain samples were stored frozen for 99 days ( 3.3 months) prior to residue analysis. There are adequate storage stability data for sorghum grain to support sample storage conditions and intervals.

The results show that the maximum combined residues of dicamba and its 5 OH metabolite were 0.174 ppm in/ on sorghum grain harvested 74 88 days following a single post directed spray application at 0.25 lb ae/ A ( 0.5x). The maximum combined residues were 3.164 ppm in/ on sorghum grain harvested 30 34 days following the last of two applications for a total rate of 0.5 lb ae/ A ( 1x).

Wheat grain MRID 44089305 ( DP Barcode D228703, 7/ 16/ 98, S. Chun)

Established tolerance( s): A tolerance of 2.0 ppm has been established for the combined residues of dicamba and its metabolite ( 5 OH dicamba) in/ on wheat grain [ 40 CFR § 180.227 ( a)( 1)].

Uses to be supported: According to the Dicamba Master Use Profile ( see Table 4), the DMA, Na, DGA, and IPA salts of dicamba will be supported on wheat at a maximum single application rate of 0.5 lb ae/ A and a maximum yearly rate of 1.0 lb ae/ A. In conjunction with PP# s 6F4604 and 4F3041 ( DP Barcode D249098, 10/ 13/ 98, W. Donovan), the registrant has submitted a revised Section B specifying a 7 day PHI for wheat.

Conclusions: There are Craven replacement data ( MRID 44089305) depicting residues of dicamba and 5 OH dicamba in/ on wheat grain. These data, however, do not support the maximum seasonal rate of 1.0 lb ae/ A that is listed in the Dicamba Master Use Profile because the wheat trials were conducted at application rates of 0.25 or 0.5 lb ae/ A. The combined residues of Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 46 of 94 dicamba and 5 OH dicamba ranged from < 0.01 to 0.15 ppm in/ on samples of wheat grain harvested 63 125 days following one spring broadcast application of representative dicamba salt formulations at 0.25 lb ae/ A ( 0.5x). The combined residues ranged from 0.039 to 1.4 ppm in/ on grain samples harvested 6 12 days following the last of two treatments for a total of 0.5 lb ae/ A ( 0.5x).

For the purpose of reregistration, the registrants are required to submit a complete set of residue data on wheat grain reflecting a maximum seasonal rate of 1.0 lb ae/ A. Alternatively, the registrants may rely on the available data provided they are willing to revise product labels for consistency with the reviewed data. If the registrants elect to choose the latter option, then they will be required to revise product labels to specify a maximum seasonal rate of 0.5 lb ae/ A. The existing tolerance of 2.0 ppm for wheat grain will be considered adequate if the registrants elect to revise product labels.

Discussion of data: The submission for MRID 44089305 depicts magnitude of the residues of dicamba and 5 OH dicamba in/ on wheat grain. A total of 20 field trials were conducted during the 1995 growing season in 16 states: CO( 2), ID, IL, KS( 2), MN, MO, MS, MT( 2), NE, NM, NC, ND, OH, OK( 2), TX, and WY. These states cover EPA regions II ( 1), IV ( 1), V( 5), VI ( 1), VII ( 5), VIII ( 6), and XI ( 1). Geographic representation of data is adequate since the number and location of wheat trials is in accordance with Tables 1 and 5 of GLN 860.1500. The wheat field trials were conducted using the following salt formulations of dicamba: DMA, DGA, and Na.

Two treatment patterns, designated as A and B, were employed in this study. Treatment A consisted of a spring broadcast application at 0.25 lb ae/ A ( 0.25x) made to the crop immediately prior to first joint ( POPO1). Treatment B consisted of Treatment A plus a preharvest broadcast application at 0.25 lb ae/ A, made 7 days before harvest ( POPO2) for a total of 0.5 lb ae/ A ( 0.5x). The DMA salt formulation of dicamba was applied in 10 trial locations. Side by side trials with the DMA, DGA, and Na salt formulations of dicamba were conducted at four trial locations to compare the residues found from use of the different salt formulations.

Samples were analyzed for dicamba and 5 OH dicamba using a GC/ ECD method ( Sandoz Method AM 0691B 0593 3) with a limit of detection of 0.01 ppm. The adequacy of the method for data collection was validated by fortifying untreated grain samples with dicamba and 5 OH dicamba at 0.010, 0.020, 0.10, and 1.0 ppm. Method recoveries were within the acceptable range. Wheat grain samples were stored frozen for 35 197 days (~ 1 7 months) prior to residue analysis. There are adequate storage stability data available for field corn matrices which may be translated to wheat grain.

The results indicate that the total residues ( dicamba + 5 OH dicamba) in/ on all treated grain samples ranged < 0.01 0.15 ppm for Treatment A ( 0.25x) and 0.039 1.4 ppm for Treatment B ( 0.5x). Analysis of Variance ( ANOVA) statistical analysis was performed on the data collected from the four locations where the DMA, DGA, and Na dicamba salt formulations were used. The results indicate that the difference in the magnitude of the residues observed in grain was influenced by the difference in the trial locations and not by the differences in the dicamba salt formulations. Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 47 of 94 Forage, Fodder, and Straw of Cereal Grains ( Crop Group 16)

Barley hay and straw MRID 44089304 ( DP Barcode D228703, 7/ 16/ 98, S. Chun)

Established tolerance( s): Tolerances of 2.0 ppm and 15.0 ppm have been established for the combined residues of dicamba and its metabolite ( 5 OH dicamba) in/ on barley hay and straw, respectively [ 40 CFR § 180.227 ( a)( 1)].

Uses to be supported: According to the Dicamba Master Use Profile ( see Table 4), the DMA, Na, DGA, and IPA salts of dicamba will be supported on barley at a maximum single application rate of 0.25 lb ae/ A and a maximum yearly rate of 0.38 lb ae/ A.

Conclusions: There are Craven replacement data ( MRID 44089304) conducted at application rates of 0.125 or 0.375 lb ae/ A. The combined residues of dicamba and 5 OH dicamba were < 0.02 1.876 ppm in/ on samples of barley hay harvested 7 days following one broadcast application made to the crop prior to first joint stage using representative dicamba salt formulations at 0.125 lb ae/ A ( 0.5x). The combined residues were 0.388 10.519 ppm in/ on barley straw samples harvested 7 days following the last of two treatments ( with the first made prior to joint stage followed by a preharvest treatment) for a total of 0.375 lb ae/ A ( 1x). The existing tolerances of 2.0 ppm and 15.0 ppm for barley hay and straw, respectively, are adequate.

Discussion of data: The submission for MRID 44089304 depicts magnitude of the residues of dicamba and 5 OH dicamba in/ on barley hay and straw. [ It is noted that this study also included data for barley forage which are not presented herein because forage is not a significant commodity of barley as per Table 1 of GLN 860.1000.] Eleven field trials were conducted in CA, ID, MN, MT, ND( 2), OR, PA, SD( 2), and UT. A field trial was also conducted in WY but no samples were collected from this trial site. Geographic representation of data is adequate as the number and location of barley trials is in accordance with Table 1 of GLN 860.1500. The barley field trials were conducted using the following salt formulations of dicamba: DMA, DGA, and Na.

Two types of treatments were used. Treatment A ( POPO1) consisted of one broadcast application at 0.125 lb ae/ A, made to the crop immediately prior to first joint stage. Treatment B ( POPO2) consisted of Treatment A plus a preharvest broadcast application at 0.25 lb ae/ A, made 7 days before normal harvest. The DMA salt formulation of dicamba was applied in five trial locations. Side by side trials with DMA, DGA, and Na salt formulations of dicamba were conducted at four different trial locations. Samples were analyzed for dicamba and 5 OH dicamba using a GC/ ECD method ( Sandoz Method AM 0691B 0593 3) with an LOQ of 0.01 ppm. The adequacy of the method for data collection was validated by fortifying untreated hay and straw samples with dicamba and 5 OH dicamba at 0.01 4.0 ppm. The average method recoveries for the field trials were acceptable (> 70%) for all barley commodities. However, the HED review noted that the method was not validated over an acceptable range since residue levels in barley straw were found well above the ranges of the method validation. The HED review, thus, requested additional method validation at a spike level of up to 15 ppm for barley straw. Barley Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 48 of 94 hay samples were stored frozen for 40 160 days (~ 1 5 months), and barley straw samples were stored frozen for 27 177 days (~ 1 6 months) prior to residue analysis. There are adequate storage stability data available for field corn matrices which may be translated to barley hay and straw.

The results of Treatment A indicate that residues of dicamba per se in/ on barley hay and straw were < 0.01 1.046 ppm and < 0.01 0.251 ppm, respectively. Residues of 5 OH dicamba ranged as follows: < 0.01 0.830 ppm in/ on barley hay and < 0.01 0.375 ppm in/ on barley straw. The total residue levels ( dicamba + 5 OH dicamba) were < 0.02 1.876 ppm in/ on barley hay and < 0.02 0.626 ppm in/ on barley straw.

The results of Treatment B indicate that the residues of dicamba per se were 0.331 10.466 ppm in/ on barley straw. The residue levels of 5 OH dicamba were < 0.01 2.058 ppm in/ on barley straw. The total residue levels ( dicamba + 5 OH dicamba) were 0.388 10.519 ppm in/ on barley straw. The statistical analysis performed by the registrant indicated that there was no significant difference in the magnitude of the residue samples based on formulation.

Corn, field, forage and stover MRID 44089303 ( DP Barcode D228703, 7/ 16/ 98, S. Chun)

Established tolerance( s): A tolerance of 3.0 ppm has been established for the combined residues of dicamba and its metabolite ( 5 OH dicamba) in/ on field corn forage and field corn stover [ 40 CFR § 180.227 ( a)( 1)]. A generic tolerance of 0.5 ppm is also established for the combined residues of dicamba and its metabolite ( 5 OH dicamba) in/ on " corn forage" and " corn stover" [ 40 CFR § 180.227 ( a)( 1)].

Uses to be supported: According to the Dicamba Master Use Profile ( see Table 4), the DMA, Na, DGA, and K salts of dicamba will be supported on field corn at a maximum single application rate of 0.5 lb ae/ A and a maximum yearly rate of 0.75 lb ae/ A.

Conclusions: There are Craven replacement data ( MRID 44089303) depicting residues of dicamba and 5 OH dicamba in/ on field corn forage and fodder ( stover). These data represent not only the application specifically listed for corn, but also the use on fallow agricultural soils at 2 lb ae/ A for a total rate of 2.75 lb ae/ A. The combined residues of dicamba and 5 OH dicamba ranged from < 0.01 to 2.27 ppm in/ on field corn forage harvested 39 71 days following the last of three sequential treatments ( 2.0 + 0.5 lb + 0.25 lb ae/ A) of crop using representative dicamba salt formulations for a total of 2.75 lb ae/ A. The combined residues ranged from < 0.01 to 2.45 ppm in/ on field corn fodder harvested 66 123 days following same sequential treatments. The existing tolerances of 3.0 ppm for field corn forage and fodder are adequate.

Discussion of data: The submission for MRID 44089303 includes data from a total of 20 field corn trials conducted between 1994 1995 in 16 states: IA( 2), IL( 2), IN, KS, KY, MN( 2), MI, MO, NE( 2), NC, ND, OH, OK, PA, SD and WI. These states cover EPA regions I ( 1), II ( 1), V ( 17), and VI ( 1). Geographic representation of data is adequate since the number and location of field corn trials is in accordance with Tables 1 and 5 of GLN 860.1500. The DMA salt Dicamba Summary of Analytical Chemistry and Residue Data Barcode: D317703 49 of 94 formulation was applied in 12 trial locations. Side by side trials with the DMA, DGA, and Na salt formulations of dicamba were conducted at 8 trial locations to compare the residues found from use of the different salt formulations.

Three broadcast applications of dicamba were used on each treated plot at each site. The first application at 2.0 lb ae/ A was made to crop stubble, fallow or bare ground in the fall of 1994 prior to ground freeze, with subsequent planting of field corn in the spring of 1995. The second application at 0.5 lb ae/ A was made in the spring to 8 inch tall field corn. The last application at 0.25 lb ae/ A was made in the spring or summer to 36 inch tall field corn. The total applied rate was 2.75 lb ae/ A ( 3.7x the maximum yearly rate listed in the Dicamba Master Use Profile). Samples of field corn forage were collected at a PHI range of 39 71 days whereas fodder PHIs ranged 66 123 days.