Prevention and Protection Part Four

With the recent rain and pop up thunderstorms, gray leaf spot, downy mildew and other diseases have been flourishing in the area. Japanese Beetles have also gone to town on our ornamentals, especially roses and crepe myrtles. Mosquitoes are going crazy (monitor your yard for areas that collect water and drain them, preventing the mosquito from breeding).

Gray leaf spot (Pyricularia grisea) goes with St. Augustine like grits go with shrimp! Or like chinch bugs go with St. Augustine! To battle gray leaf spot you are best employing many cultural practices and using limited control products if necessary.

 Gray leaf spot looks like someone burned or dripped acid on the leaves of the plant.  There are little oblong spots on the leaf.  Eventually, these spots grow together and the leaf blade dies.  Whole areas of your grass can disappear at once when these leaf blades die.

Culturally there are several things to do to minimize your problem with gray leaf spot.  This disease likes high humidity and excessive nitrogen fertilizer.  To help alleviate the high humidity, mow your grass to a level that seems abnormal to St. Augustine.  Try to get it down to 2 ½ - 3 inches depending on the variety of St. Augustine grass.  Also try to mow every 3 – 5 days with a bagger.  This mowing will help get sunlight down to the crown of the plant, drying the leaf blades as quickly as possible. Skip the gym and mow!

Gray Leaf Spot likes hot humid weather.  Minimize the amount you water as much as possible.  Wait until your lawn is getting a blue/green color and your foot prints stay in the lawn after you walk across it before you water. Unfortunately, you can not control rainfall as easily. In the Lowcountry, afternoon thunderstorms are a way of life, so keep the grass mowed as low as you can so it will dry out quickly.

Since the Lowcountry dries out very quickly when the rain stops, the use of a wetting agent like Possum’s Wetting Agent with Biostimulants will help reduce supplemental watering. Using wetting agents also helps reduce the amount of dew that remains on the leaf blade. Dew can really make diseases spread. On golf course greens we would go out with a dew whip to get the dew off the leaf blades of the grass. A dew whip is a very long fiberglass pole that would slide across the top of the grass, knocking the dew off of the blades of grass so the grass would dry.   

Hold off of the nitrogen fertilizer until you can get this disease under control.  If you need some color you could add a product like Possum’s Minors to give you some green without all the nitrogen. A healthy lawn is less apt to get diseased and recovers quicker from any pests that might damage it. Having a soil test done and following a program to get the nutrients that the test recommends is an easy preventive step that you can take to improve the overall appearance and health of your yard. Do you need potassium, magnesium?

With the conditions as favorable as they have been, a preventive application of Disarm would be a good idea (this product will give you up to 28 days control). If you have to resort to a control product, make sure the product is labeled for Pyricularia grisea.  There are many leaf spot diseases on labels of control products but only certain ones work on gray leaf spot on St. Augustine. We had one customer come in that had been applying a product that controlled Drechslera spp. and Biopolaris spp. leaf spot; however, the product was not labeled for Pyricularia grisea (watch where you shop). 

Honor Guard, Disarm, Cleary’s 3336 and Heritage are systemic products that you spray. Since this is a leaf spot fungus, the sprays seem to give good coverage over the leaf blade.  If you insist on a granular product, Prophesy G (same active as Honor Guard and Banner), Cleary’s 3336 G or Disarm G are granular systemic products that will do a good job for you. When controlling a leaf spot disease, rotate your chemicals. Whether you spray or use a granular, these products will come up through the root system. Always read and follow product label.

I’m already way over my column inches for the week, so I guess Japanese Beetles can wait until next week. At the three Possum stores we send out e-mails to people on our e-mail list when we get an outbreak of insects or disease, are having gardening talks, or any other relative information. Just go by the store and sign up – that easy – and it is free! We also promise to protect your privacy and not bombard your inbox. We also post updates on our website (www.possumsupply.com).

Prevention and Protection Part Three

Prevention and protection is the only way to be successful in controlling certain pest. Boring insects, sod webworms, “the nasty rascal, the chinch bug”, roaches, and termites are just a few more.

Borers are generally moths or beetles as adults. They fly around and lay eggs on leaf petioles (where the little stem that comes off a leaf attaches to the main stem), cracks in the bark, or wounds in the plant.

Generally, when the egg hatches, a larva emerges and tunnels inside the twig, tree, or vine. The larva is the part of the life cycle that does the damage. Since  larva get inside the tree, it makes it very difficult to control with spray or dust applications. The borer overwinters as a larva and emerges generally in the spring as an adult.

Treating the tree (not a fruit, nut, or vegetable producing tree) with a systemic product like Dominion or Safari as a ground drench as well as spraying the tree to protect the tree from adults that are laying eggs and an oil product to suffocate eggs is a good strategy for high value trees. Depending on the borer, you would target your spraying when the adults are active (usually in the spring).

Prevention is critical with borers because once they are inside the tree or plant, the plant protects them.

Pest Management Professionals do a great job of protecting our homes from termites. You would not want to watch your house get eaten up then think, “hey, I might have a problem with my house. The second story toilet just fell through the floor with my mother-in-law on it.”

Termites do a lot of damage very quickly. The cost of protecting your house to prevent the damage is very low. If you have a reputable Pest Management Professional do the work, their insurance should cover any damage unless you violated the contract (example – added on a porch and did not let them know).

Termites are one insect that should be left to a professional to control. Termites attack what is generally our highest price asset – our home.

While working in my yard last night, I did see a few sod webworm moths. They’re back!

Prevention and Protection part 2

Lace bugs, aphids, white flies, borers, chinch bugs and scale are all insects that are better to prevent or protect your plant from before the insects attack.

Lace bugs, aphids, white flies, and scale attack ornamental plants and trees and generally suck the sap out of the plants leaves for the sugar and nutrient value. The insect does not have to suck, like we do with a thick milk shake, because the plant’s system is pressurized and the plant juices come out on their own like air out of a tire.  

Lace bugs, aphids, white flies, and scale are very host specific (like the taste of certain plants). There are many types of lace bugs. Some of their favorite plants and trees include sycamores, azaleas, lantanas, and oak trees. Aphids love crepe myrtles and roses. White flies attack gardenias and citrus. Scale is common on camellias, magnolias, sago palms, and hollies.

Lace bugs, aphids, white flies, and scale suck vital fluids from the plant, but the worst consequence is the sooty mold that grows on some of these insect’s excrement (poop). These insects have a very small digestive tract and a lot of the plants fluid passes through them undigested and a mold call sooty mold grows on the poop. This black sooty mold gets all over whatever is around the plant.

The sooty mold from a tree like a crepe myrtle could get on under lying plants, porches, houses, cars, driveways, swing sets and anything else in the area as well as the crepe myrtle itself making a huge mess and ruining paint jobs.

The sooty mold blocks light that is trying to get to the leaves to perform photosynthesis. A plant feeds itself by getting sunlight to the leaves, so the plant can starve to death or certainly be weakened if the sooty mold is covering the plant.  

Lace bugs, aphids, white flies, and scale poop, also called honey dew (not to be confused with “ honey do list”), also attracts small, sugar feeding ants (Argentina ants) that can get in your house and be a problem.

You probably know if you have a history with these sucking bugs, so you can target certain plants. Dominion has many formulations to meet your needs (even Dominion Fruit & Vegetable for your citrus). The best way to use this product is as a drench; therefore, no beneficial insects are harmed. The product will usually provide season long control of these different pests if used as a systemic drench. The active ingredient is in a class of chemistry that acts on something insects have and use and mammals do not. This same active ingredient is used as a spot treatment on dogs for fleas and other pests.

Neem oil and IC3 are organic solutions to these sucking bugs.

Prevention and protection will avoid a sooty, poopy mess!

Think Prevention / Protection

Watch out for those insects that suck juice out of plants and animals.  Fleas, chinch bugs, mites, lace bugs, aphids, white flies, and scale have been real bad this spring with the dry weather. Mosquitoes anyone?  Powdery mildew (a fungus) has been very bad on the new growth of crepe myrtles, dogwoods, roses and verbena. Twig borers have been active on magnolias, oaks and dogwoods. The grilling season will bring flies to the party. Rats, mice and other varmints including roaches will be looking for a cool house or crawl space to call home.

With all the above prevention or protection is a lot easier than curative action. Think of sunburn and applying sunscreen. It is a lot quicker and easier to apply sunscreen than to have a painful burn that may have long term expensive consequences. First you have discomfort, then visits to dermatologist, then moles remove, then possible cancer, then…  

If you grow squash, look around the plants and see if there is any sawdust material.  Also, cut lengthwise along the vine and see if there is a white grub-like worm in your squash vine.  Inside the vine that you have cut, you should also see the same sawdust.  Look for any holes along the stem of the plant as well.  If you see any of these signs, you have squash vine borer.

At this point there is not a lot you can do other than try to bury the vine and hope it re-roots at a node, so water and nutrients can be translocated to this point directly from the roots of the plant. 

Squash vine borer is a tricky kind of guy.  The female adult flies around in April and May and deposits eggs on the vines.  The moth (the adult) flies similar to a dragonfly and and has metallic green wings and a reddish orange body.  The eggs then hatch and the white larva (the guy that does the damage) bores into the stem and begins to feed.  By feeding inside the stem, they cut off the ability for the plant to move water and nutrients through the stem.  This is what makes it wilt and die so fast!  After the larvae feed on the plant for 4-5 weeks, they crawl out of the stems and pupate.  They overwinter as pupae until next spring when they become adults, and the cycle continues.

The control of this borer should be a multi-faceted approach. 

·         Remove the infected vines, hopefully along with the larvae. 

·         Regularly till your garden throughout the fall and winter to destroy over-wintering cocoons (i.e. pupae).

·         Plant very early spring to get ahead of their life cycle. 

·         Keep your eye out for the moth and remove eggs as you see them appear.

·         During April and May of next year (the egg laying period), consider using an insecticide that contains methoxychlor (DMDT, Metox).

Always read, understand and follow product label. The product label is a Federal Law.

Bill Lamson-Scribner can be reached during the week at Possum’s Landscape and Pest Control Supply. Possum’s has three locations 481 Long Point Rd in Mt. Pleasant (971-9601), 3325 Business Circle in North Charleston (760-2600), or 606 Dupont Rd, in Charleston (766-1511). Bring your questions to a Possum’s location, or visit us at http://www.possumsupply.com. You can also call in your questions to “ The Garden Clinic”, Saturdays from noon to 1:00, on 1250 WTMA  (The Big Talker). The Horticulture Hotline is available 24 / 7 at possumsupply.com.