Sunday, May 29, 2011

Take a Powder

One of my good friends called me the other day with a problem. It looked like somebody had taken baby powder and sprinkled it on one of his Citrus trees. After a little discussion, I concluded it was Powdery Mildew. This is somewhat unusual, not completely out of the question, but not one of your ordinary Citrus problems either.
Powdery Mildew is a fungal disease that does affect a wide range of plants. It is actually caused by many different species of fungi in the order Erysiphales. It is one of the most widespread and luckily, easily recognized plant diseases.
As many of you know, I am NOT a fan of Crepe Myrtles. There are many other reason, but one of them is their susceptibility to Powdery Mildew. Here we are at the end of May and I already have a wicked case of it:


Even though there are several types of Powdery Mildew fungi, they all produce similar symptoms on plant parts. Powdery Mildews are characterized by spots or patches of white to grayish, baby powder like growth, however leaf curling and twisting may be seen before the fungus is noticed. While it is not usually considered fatal, plant damage can occur when the infestation is severe, and if left untreated, it can eventually kill the plant. On vegetable plants, Powdery Mildew will weaken the taste and quality of the produce. It can also stunt plant growth and distort the shape of buds, blooms and fruit. It can cause leaves to turn yellow and drop prematurely.

Powdery Mildew on Squash

The fungus survives the Winter attached to plant parts and plant debris such as fallen leaves. This is one reason why I stress sanitation in the yard and garden. Clean up any leaves, dropped fruit, or dead plant matter as soon as the crop is done. When the weather warms in Spring, the process begins.
As the daytime temperatures rise above 60 degrees the fungi responsible for Powdery Mildew begin to produce spores which are dispersed into the air. Infections occur when they contact a suitable host and environmental conditions are favorable. The severity of the disease depends on many factors, such as variety of the host plant, age and condition of the plant, and weather conditions during the growing season.
Powdery Mildews are severe in warm, dry climates. This is because the fungus does not need the presence of water on the leaf surface for infection to occur. However, the relative humidity of the air does need to be high for spore germination. While high relative humidity favors spore formation, low relative humidity favors spore dispersal, which explains why Powdery Mildew tends to be a problem when the days are cooler and the nights are humid. Temperature can also be a factor. Although Powdery Mildew can occur all season long, it is less common during the heat of the Summer.

Early Stages of growth

If there is one good thing about the Powdery Mildews, it is this, they are host specific. This means they cannot survive without the proper host plant. For example, the species Uncinula necator, which causes Powdery Mildew on grapes does not attack lilac. Similarly, Microsphaea alni which affects elm, lilac and oak, does not affect turfgrass.
How does one go about to control this pest? As with all diseases, optimum plant health is the first line of defense. Make sure your plant is well watered, fed, and growing in the correct place. Avoid planting sun loving plants in shady areas, especially very susceptible plants.
Purchase only top quality, disease-free plants of resistant cultivars and species from a reputable nursery, greenhouse or garden center.
If the disease has already become an issue in your yard:
Avoid late Summer applications of nitrogen fertilizer. When you apply high levels of nitrogen late in the season it produces new tender growth which is more susceptible to infection.
Do not compost infected plant debris. Temperatures often are not hot enough to kill the fungus in the average homeowners compost bin. Burn it or dispose of it in the trash.
Selectively prune overcrowded plant material, or space the plants for good air circulation. This helps reduce relative humidity.
Remember to sanitize garden tools to prevent them from carrying the spores elsewhere.
If you have attempted the above cultural controls and are still having a problem, there are many fungicides out there to help. Please follow the instructions on the fungicide label for use on specific plant species, varieties, rates to be used, timing of applications, and waiting periods before harvest. This is the law!
For best results with fungicides, spray programs must begin as soon as mildews are detected. When ranges are given, use the shorter interval during cool, damp weather. Be sure to cover both the upper and lower surfaces of the leaves.
Something else to consider, is a late season spray of fungicide worthwhile if the plant is deciduous? The leaves have already produced food for the plant and are going to fall off soon anyway. Just be sure to rake and dispose of them as they fall. Sanitation, Sanitation, Sanitation!
There are some homemade remedies out there. I don't or won't recommend them, they can be useless or dangerous, but thought you should at least know about some of them. I have heard of people using one part milk with 2 parts of water and spraying every 3 to 4 days at the first sign of mildew.
How about the use of mixing 3 tablespoons of apple cider vinegar with one gallon of water and spraying every few days.
Then there is this, researchers at the University of Rhode Island have confirmed that a combination of 1 tablespoon baking soda plus 2.5 tablespoons light horticultural oil in 1 gallon of water is effective against Powdery Mildew on roses.
I would like to say again, the use of homemade remedies can be useless or in some extreme cases, dangerous to you or the plant. Please use caution if you decide to go that route.
One last thing, for all you plant geeks out there, and I count myself as one of you.....the Powdery Mildew that is attacking my Crepe Myrtle is Erysiphe lagerstroemiae.....luckily, that is it's only host.
Happy Growing!

Sunday, May 22, 2011

They Mite..... If You Let Them!

This past week I did a program on growing fruit in the Lowcountry. I basically did a ten minute presentation, which was WAY too short to do anything of substance, then the other two on the panel did the same. After that it was almost an hour of "Stump the Chump" style questions. The one gentleman was a small fruit farmer from the Edisto area and the other was the host of the TV show "Making it Grow", Rowland Alston. I only bring that up because you would figure that he would get the majority of the questions, being a big star and all.....Nope, probably 70% of the questions were directed at me and Citrus.
There was one question however that the three of us kind of teamed up on, and that was about Spider Mites.
Spider mites belong to the family, Tetranychidae. They are classed as a type of arachnid, which are relatives of insects that also includes, spiders, ticks, and scorpions.
These microscopic creatures are pests to over 180 species of plants including many fruit trees, vines, berries, vegetables,and ornamental plants.
Spider mites are less than 1 millimeter in size and vary in color. They are difficult to see with the naked eye.
Under a very good microscope, they look like this:
Creepy little things, aren't they?
Spider Mites, as you can see, have a simple, oval‑shaped body and no wings or antennae. All species pass through an egg stage, a six‑legged larval stage, and two eight‑legged nymph stage before transforming into an eight‑legged adult. Immature stages resemble the adults except in size. They reproduce rapidly in hot weather and commonly become numerous in June through September. An adult female may live for several weeks and lay many dozens of eggs during her lifetime.
The damage they do is caused as they feed, bruising the cells with their small, whiplike mouthparts and ingesting the sap. Injury can lead to leaf loss and even plant death. Damaged areas typically appear marked with many small, light flecks, giving the plant a somewhat speckled appearance.
Photo courtesy of Clemson University

They can also cause a bronzing effect of the leaves,similar to this:

One last sign that you might have Spider Mites is the webbing on heavily infested plants:

If you are unsure whether you have Mites or not, there is an easy test. Place a white piece of paper or paper plate under your plant and give it a decent shake. If you see tiny little specks wandering around, you have them. The size of the Spider Mite "specks" on the paper is about the same size as the period at the end of this sentence.
How do you control them? Irrigation and moisture management can be important cultural controls for spider mites. Adequate irrigation is important because water stressed plants are most likely to be damaged. Keeping the plants in a high humidity environment encourages pathogenic fungi that attack the mites.
Various insects and predatory mites also feed on spider mites and can provide some level of natural control. One group of small, dark-colored lady beetles known as the "Spider Mite Destroyers" (Stethorus species) are specialized predators of Spider Mites.
Courtesy of UC Davis

Then you have the Minute pirate bugs (family Anthocoridae)
Courtesy Bug

Big-Eyed bugs (Geocoris species)

and Predatory Thrips
Courtesy Bug

Which can all be important natural enemies.
Chemical control of spider mites generally involves pesticides that are specifically developed for spider mite control (miticides or acaricides). Few insecticides are effective for spider mites and many even aggravate problems because they kill the beneficial insects. Plus, most miticides do not affect eggs, so a repeat application approximately every 10 to 14 days is usually needed for control. Then to top it all off, spider mites can become resistant to certain pesticides.
Some control can be obtained with horticultural oils, like Neem oil, and insecticidal soaps. These materials have no residual activity and must come in direct contact with the mites. House plants can be tricky. There is no biological control. You can use the oils and soaps, but one easier method is to periodically hose small plants in the sink or shower.
Some of the mites that you may encounter are:
The Twospotted Spider Mite (Tetranychus urticae)
This is the most common and destructive mite on deciduous ornamentals. It has an extremely wide host range and will feed on many varieties of trees, shrubs, flowers, weeds, fruits, greenhouse and field crops. Immature mites and adults are yellowish to greenish with two dark spots on either side of the body.
European Red Mite (Panonychus ulmi)
This mite attacks deciduous trees and shrubs and is especially common on flowering fruit trees such as Apple and Crabapple, Cherry, Pear, Plum, Hawthorn, and Serviceberry.
Southern Red Mite (Oligonychus ilicis)
This is the most common and destructive spider mite on broad‑leaved evergreens, especially Japanese and American hollies, Azaleas, Viburnum, and Roses.
This is just a brief discussion of these pests, there are many more out there and much more that can be said about them. Your best defense is to just keep a good eye out. When scouting for Spider Mites, pay particular attention to plants having a history of mite problems. Spider Mites often re‑infest the same plants year after year. The good news, plants will often recover after the Mites have left as long as there was not too much death!
Happy Growing!

Sunday, May 15, 2011

Quarantine Explained

I have been getting a lot of questions lately, pertaining to the quarantine here in Charleston on Citrus. It is Springtime and the desire to plant things is obvious. With the push to grow your own veggies and fruit, it is no wonder people want to grow their own Citrus.
The questions I keep getting are, "I want to grow some Citrus, but can't get any because of the quarantine". Unfortunately, there has been a lot of confusion as to how the quarantine works. I wanted to set the record straight.
Let me start at the beginning.
The reason for the quarantine is because of Citrus Greening. A couple of years ago a Grapefruit tree was discovered to have the disease in downtown Charleston. I have done a couple of blogs on the topic, you can read them here:
So I won't bore you with the details here.
Charleston County, the county I live in, and Beaufort County is under quarantine for both the Asian Citrus Psyllid and Citrus Greening. This means that Citrus can not LEAVE these counties. You can bring it in however.
So, if you live in neighboring Dorchester County and have a Citrus tree, you can bring it to Charleston County. Just be ready to leave the tree here. This also goes for the example of, if you live in Dorchester County and come to a big box store that happens to be selling Citrus trees in Charleston County, you LEGALLY can not buy that tree and take it home. Sure you can do it, the police and store employees are not checking drivers licenses, but it is still illegal. I can not even give a gift of a Citrus tree to anybody outside of my quarantine area.
Hopefully this clears that up a little. I know what you are thinking, then WHY are the big box stores selling Citrus trees if there is a chance of illegal exportation? The best answer I can come up with is, they don't know! I have asked many store managers that very question, I basically get the, "We sell what they ship us". So somewhere along the line there is a disconnect. I am trying to fix this in my small part of the world.
If you really want to know where the quarantines exist and learn more about this situation, check out this excellent website by the USDA:
The reason behind this blog today is to help clarify the quarantine of Citrus. Now, I am going to muddy the waters a little. Yes, you can basically bring Citrus from anywhere, other than from a quarantine area, into another area, unless you are a Citrus producing state. These states are, Florida, Texas, California and Arizona. You can not legally ship anything Citrus into these states. I had a person in Texas ask me how to get some Citrus seeds into her state, I told her THAT is even illegal. I sent her this from the Texas Department of Agriculture:

Part I. Texas Department of Agriculture
Chapter 5. Quarantines
Citrus Seed, Citrus Budwood, and Citrus Nursery Stock Quarantine
4 TAC sec.5.152, sec.5.153
The Texas Department of Agriculture proposes amendments to sec.5.152 and
sec.5.153, concerning restricted shipments of Citrus Seed, Citrus Budwood, and
Citrus Nursery Stock. The department proposes amendments sec.5.152 and sec.5.153
to include the State of California. Currently, citrus seeds, citrus budded
nursery stock or seedlings, citrus budwood, or any part of any citrus tree or
seedling may not be shipped, carried, or in any way transported by any means
into the State of Texas. Florida is the only state allowed to ship into this
state under certain conditions. It is necessary to amend the restricted shipment
section and the restrictions on citrus seed shipment section to include
California as a state from which citrus products may be imported because
California is a disease-free source of certified citrus budwood and citrus seed
for Texas producers.

Sorry about the legalize, but I wanted to show the information in its truest form. I would imagine that all of the Quarantine areas have similar statements.
There are some places that are authorized to ship into these Citrus producing states, but be careful, if you are shopping online they should state where they can ship to......make sure you ask. They have special authorization because of the way they grow their trees, either under screening or greenhouses. I have heard of Citrus tree shipments being confiscated because of illegal exportation.
Along these same lines, Yes, you can purchase a Citrus tree in Florida almost anywhere along I-95 and bring them back to your hometown. Again it is illegal! I have seen the federal order and it states that no leaves, twigs, stems, plants, trees, scions or cuttings can be moved from a quarantine area. This includes county and state lines. 
If you have any doubts whether you live in a quarantine area or not, I urge you to please check out the Save our Citrus website. Just in case here it is again:
I hope this sets the record straight and more or less makes sense. I want everybody to have happy, healthy Citrus trees! Please, if you have any questions, feel free to contact me. 
Happy Growing!

Sunday, May 8, 2011

Mothers Day 2011

A little change of pace. Today is Mothers Day in the United States, I don't know if any other country observes this, if they don't, they should. Everybody out there will tell you that Mothers are "superwomen" or that their Mother is the best. Well, let me tell you, if you REALLY want a Super Mom, mine wins hands down!
Most people that know me don't know that my Father passed away when I was in 2nd grade, making me all of 7 or 8 years old. At the time, I had only 1 younger brother and 1 younger sister...My littlest brother came from another marriage. So, at the ripe old age of 27, my Mother was now alone with three very young children...ages 8-5-3.
To this day, I have NO IDEA how she managed to raise us. Yes, her parents helped some, we saw my grandparents on the weekends, but that was about all. We lived in an old farmhouse, when I say old, it was 100+ years old then. This was up in New Jersey. The house was basically in the woods, we had a few neighbors across the street, but they were much older. There were no kids around to play with, other than each other.
Thinking back, we always had food on the table. Christmas and Birthdays were amazing. Every year just before school started we went shopping for new clothes, remember this was LONG before Wal-Mart came on the scene, we went to Sears, that was the only place that had clothes to fit my skinny brother and my fat bleep.
This was also back when they had classroom Mothers. These Mothers would come in and assist with classroom birthday parties, arts and crafts, and who knows what else behind the scenes. My Mother was at every function I can think of!
Abraham Lincoln once said: “All that I am, or hope to be, I owe to my angel mother”. No truer words have ever been spoken. My mother taught us about friendship, safety, kindness, nature and you know where I got THAT part of my life from. She also taught us about laughter. I mentioned above some of the things she taught me, let me demonstrate:
My sense of clothes:

Safety, it was dangerous to ride wild animals:

And of course, cleanliness:

I mentioned laughter, I got her sense of humor too, warped!
But seriously, there is a part of Mothers Day that I hate. Every jewelry store, department store, and any other store you can think of, tell you to buy your Mother this, that or the other thing to show her how much you love her. I would love to if I could afford it, I would buy her everything under the sun, but it wouldn't mean anything. Abraham Lincoln also said one other great thing: “No gift to your mother can ever equal her gift to you - life”.
Mother because of you, I am what I am...I had an absolute wonderful childhood, and I would not change it for anything......There is also no way in the world I can ever Thank You enough!!!
p.s. She will kill me for this picture, but I had to end today with my two favorite flowers:
Wife on the left, Mother on the right