| | | Figure 1 -- River Birch Sawfly |
| | | Figure 2 -- Grubs/June Beetles |
| | | Figure 3 -- Colaspsis beetles |
| | | | | Figure 6 -- Squash vine borer |
| | | Figure 7 -- Leaf footed bugs, Cowpea curculio |
|
Ladies and Gentlemen:
The bugs are on the move, and there is a large diversity and plenty of them.
1. Aphids – There are several different species that are being reported at this time. Aphids of roses, vegetables, citrus, crepe myrtles, sugarcane, hackberry and river birch are all out. All aphids have piercing, sucking mouth parts and can damage the plants in three ways. The first is by direct feeding on the plants and taking plant nutrients. The second is by excreting the excess sugars they take in, and this sticky sweet material is an excellent medium for the development of a complex of fungi that develop into a black mat-like covering called sooty mold. This reduces the plants ability to produce food and makes it grow erratically. Third -- many aphids are capable of carrying plant diseases or of injecting the plants with toxins that can cause them to be stressed or even die. There are many controls for aphids, and when used according to label directions, they do a good job of managing these pests.
2. Carpenter bees – If only we could drill as precise a hole when we need to. Carpenter bees can be beneficial from their pollination of plants but can cause structural damage to wood on houses and furniture as well as fences or wood handles on tools (shovels, rakes, etc.). The holes are actually the nesting sites for the bees. Once the holes are constructed -- and they go for several inches -- the female bee collects a ball of pollen and then lays an egg on it and seals off the small cell and repeats the process until the tunnel is full of cells. The males are the guardians of the nest site and will dive bomb intruders and other carpenter bees. The males do not sting, but the female does. The initial tunneling is not the main problem. The problem with structure damage occurs with repeated generations year after year infesting and elongating the original tunnel so that a seven-inch tunnel this year can become twenty or thirty inches long in a couple of years. This can cause serious structural damage to the infested wood. To reduce this problem, the wood, if unpainted or lightly painted, can be treated with Tim Bor or Bora Cure. This is a borate formulation that protects the wood from injury. The wood is sprayed with water to wet it, and then the half-and-half mixture of the borate and water is sprayed on the wood and allowed to dry. This process is repeated the next day. As the wood dries it pulls the borate crystals into the wood structure, and when the bees return to bore holes, the crystals in the wood cut their mandibles and make them stop boring. Where infestations are found, a treatment with a pyrethroid and 8 ounces of liquid soap per gallon of water sprayed on the infested wood and into the holes late in the afternoon will kill or repel the bees.
3. River Birch Sawfly – Those who have river birch trees have noticed a light greenish yellow worm with a dark stripe down its back feeding on the foliage. Most assume it’s a caterpillar, but it is actually the larva of sawfly, which is actually related to the wasp family and not the butterflies. One can determine this by looking at the abdomen of the larva and noticing that it has a leg or pseudo leg on each segment. Caterpillars, depending on the family, will have from one to four pseudo legs on the abdomen. If you look real close you will see there is only one simple eye on each side of the head, as opposed to 4 to 5 simple eyes like caterpillars. The good news is that the materials used to manage caterpillars will mange this sawfly. Materials like Orthene, Malathion, Sevin, Merit and any of the pyrethroids (Figure 1).
4. Grubs/June Beetles – Two things have been happening that show that grubs and June beetles are going to be a problem this year. First, several people have called about moles tunneling their yards and about their yards being dug up at night, and second, the new foliage on their trees is disappearing at night. First, the moles and the other animals digging up the yards are an indication of the white grubs being present. They are a good food source for these animals that can seriously damage yards, flower beds and gardens. To check for grubs, turn back one square foot of sod and count the number of white grubs. If three or more are present, some sort of treatment is needed. They can be treated with Sevin or Merit or the growth regulator Mach 2. Follow label directions to get management of the problem and to avoid injury to the environment. The adults, which are June beetles or May beetles, are foliage feeders and can strip trees of their new growth. If you are noticing foliage loss, treat the trees with Sevin just before dark, and you can remove this stress from your trees. You can determine the density of the beetle population by checking around the lights outside your home at night or by checking the trees after dark (Figure 2).
5. Colaspsis beetles – These are dull, gold-looking beetles about the size of a cucumber beetle and can cause serious injury to the foliage of young pines and cypress. The adults feed on the edges of the needles and leaves and give them a sculptured look. In mid August the needles and foliage will turn brown as if the tree has been scorched or dying. Some people inadvertently cut these trees down. The trees are not dead; they are responding to the injury to the foliage caused by the beetles. The trees will re-sprout and put on foliage if they are watered and given a little nutrient. The beetles can be controlled with Sevin. Only spray if you see the beetles now; spraying in August will not control anything but may cause some additional problems (Figure 3).
6. Devil Horse – Several calls have come in from all over the state inquiring about these large black grasshoppers. These are affectionately called Devil Horses. They are usually grass and weed feeders but will get into ornamentals and gardens and some field crops. This is a problem that is caused by the hot dry weather early in the season. When hot and dry, the normal populations of organisms that prey on the grasshopper eggs and young nymphs are not functional in the soil, so high populations of grasshoppers emerge. Where populations are heavy or a nuisance, they can be managed with either Sevin or a pyrethroid (Figure 4).
7. Bagworms – These are the caterpillars that live in the brown, funny-looking cases people see hanging from their shrubs, trees and house. These bags are the housing for the bagworm larva. As it feeds, it spins the silken bag and attaches pieces of the host plant to it to blend into the system. As the foliage dries, it turns brown and becomes readily visible. They can be very damaging to infested plants depending on the density of the populations. Control of these pest caterpillars is best done in the late afternoon. Spraying in the morning is ineffective. As the day gets hot, the worms pull into their bags and rest until late afternoon. The sun's heat and the UV light will gradually break down some of the spray material so that when they come out to feed they get only a small dose of the control and may survive. Spraying in the late afternoon allows for better contact and therefore better management of the pest. They can be managed with Orthene, Sevin or any of the Bt formulations used for caterpillars (Figure 5).
8. Squash vine borer – This is a sneaky little pest in the vegetable garden. The adult moth is brightly colored in red and green and appears to be a wasp when seen in flight. The female lays her eggs on the stems, flowers and fruit of the host squash. The larva hatches and bores into the vines or crown of the plant. Its feeding causes the vine or crown to wilt and die. Cutting off and opening a wilted vine will show you the larva. They are usually not a problem until the fruit begins to set on the plants, and management is usually preventative. Sprays with Sevin, Thiodan or the Bt’s have been effective (Figure 6).
9. Leaf footed bugs – These piercing, sucking insects are primarily fruit-oriented, attacking vegetables and citrus fruits. Damaged tomatoes and peppers show visible puncture marks and are usually spotted. The feeding by this pest removes the sugars from the fruits and can inject or leave fungi in the host that causes the flesh to break down or become dry and cottony. Most fruit loose their good flavor and have little to no taste. They can be managed using Sevin, Thiodan or pyrethroids (Figure 7).
10. Cowpea curculio – If you are growing peas and the fruit is beginning to set, this is a small pest you need to watch out for. The adult is a small weevil that feeds on the seed in the pods and then lays an egg in the seeds. Many people do not know they have a problem, and many of them are eaten. Check the pods for signs of feeding, which is usually on each seed in the pods. These feeding sights are also egg deposition sites for the weevil. When these feeding punctures are noted on a few pods, this is the time to take preventative measures. Treating the plants with Sevin or Thiodan will effectively reduce the problem and allow you to grow clean peas. Application should be made about every 10 days after pod set to keep populations down. Happy eating (Figure 7).
Remember to check with your local county agent if you find something you do not know. Don’t just spray. Most of the time beneficials are the insects treated. Remember to also check your water pH before spraying to get the maximum effect from your sprays and reduce the number of applications needed. In many situations you can add ultra fine oils to assist in coverage and management of the pest. Timing of treatments is very critical, so check your plants periodically to detect problems early and reduce loss and the number of applications.
Until July,
Dale |