1. Colaspsis beetles — We normally hear about the pine colaspsis that causes the browning and injury to the needles on pine and the foliage on cypress, but this year we are seeing another colaspsis beetle – the grape colaspsis that is causing a problem on rice. These two beetles look very much alike but are host specific. They are both brownish gold in color, about the size of a cucumber beetle and found in massive numbers at some times and very low numbers at other times. The pine colaspsis adult feeds on the needles, sculpturing the edges of the needles and causing them to turn brown and die. On cypress the foliage turns red and dies. The time between the feeding, which occurs in May and June, and the observation of the injury, which usually shows in August, can be modified as it is this year. With the dry weather, we are seeing signs of the injury now. Many people think that the trees are dying; however, if you gently scrape the bark on the stems you will see the green tissue, which shows the trees are healthy. Simply fertilize and water them, and they will put out new foliage. Where beetle populations are heavy, sprays with Sevin are effective. Just check the water pH before you spray. The damage by the grape colaspsis is done to the rice root system by the larvae. Their feeding can kill young plants. The problem stems from the drilling of the rice into no-till soybean stubble. If you plant rice following soybeans next year, consider using a seed treatment, holding water on field for a prolonged period during winter, avoiding late-planted soybeans or applying permanent flood early if colaspsis found in field. Figure 1.
2. Colorado potato beetles — A common pest of potatoes may also be found on eggplant, nicotiana, petunia and some nightshade weeds. Both the adult and larval forms feed on the foliage of infested plants – the adults notching the edges of the foliage; the larvae producing a more ragged injury and defecating on the damaged tissue. Most plants can tolerate some leaf loss, but heavy injury can affect production. This is the No. 1 pest of potatoes worldwide and has developed resistance to several pesticides. Spinosad, Bacillus thuringiensis tenebrionis, Thionex and Sevin have provided management of this pest. The adults overwinter in litter around fields infested the previous year. Yellow-orange eggs are deposited on foliage as the potatoes emerge; they resemble lady beetle eggs but are larger and darker in color. The hatching larvae are orange-red and feed in clusters early. As they mature they disperse throughout the plant. At maturity they fall to the ground and pupate in the soil. There are 2 generations in the South. Figure 2.
3. Leaf miners — There are several different leaf miners that affect several plant groups. The serpentine leaf miners can be found on tomatoes, squash, eggplant, cucumbers, other melons and several ornamentals. Blotch leaf miners can be found on foliage of trees and other plants. Most assume that leaf miners are mostly little flies. While there are several, they also can be caterpillars or beetles. We normally see the pest in our gardens on both flowering plants like daisies or our vegetables like tomatoes and cucumbers. They can cause the plants to reduce bloom or reduce fruit production and either stunt or kill the plants by damaging the foliage. These pests mine between the upper and lower surfaces of the plants tissue, reducing the potential for the plant to produce food to feed itself. Control will depend on the pest involved, but most vegetables and citrus can be helped with Spinosad. The best method of control is to catch the population early and reduce damage to your plants by early treatment. Figure 3.
4. Tortoise beetle — These little beetles can be found on morning glory, sweet potato, field bindweed and kudzu and related plants in the morning glory family. Both the adults and larvae feed on the foliage creating small holes on the leaf surface. They seldom do economic injury, but the leaf riddling does attract attention and exceeds many esthetic thresholds. The adults are oval in appearance and have metallic colors – especially gold and brown. They can be mistaken for ladybeetles and are often referred to as “gold bugs.” The adults overwinter and emerge in late spring to begin their cycle. Eggs are laid singly or in small groups on the underside of the foliage, and the larvae on hatching feed on the under surface. They are somewhat flattened, spiny and vary in color from yellowish to reddish-brown. Most carry cast skins or fecal matter from the end of the abdomen. After molting 3 times, the larvae pupate attached to the leaf covered with fecal matter and other debris collected during the larval stage. Upon emerging, the adults feed for a while then go into diapauses until next year. There is only one generation per season. Figure 4.
5. Salt marsh caterpillars — We are seeing some high populations of these caterpillars with the dry weather. This hot, dry weather dries out many of the grasses and other foods they feed on along ditch banks and roads, and they become more active in search of other food sources. This can be a problem for late-planted crops or young crops like soybeans that are succulent because they will feed on them aggressively. Gardens become more attractive as well, and both flowers and vegetables can be seriously damaged. These caterpillars can vary in color from black to brown and combinations of black and orange or brown. They are no indication of how bad winter will be. Figure 5.
6. Chinch bugs — Hot, dry weather is a virtual paradise for this pest. It just loves the weather as it feeds on your grass or turf. The piercing, sucking mouthparts puncture the rhizoids and stolons of the grass and suck out the juices. This weakens and kills the grass in irregular spots and gradually merges to cover the lawn if unmanaged. The injury resembles the damage you get in the cool, wet winter season from brown patch. The chinch bugs are black-and-white in color. Eggs are deposited in the sod, and the hatching nymphs are black with a red band across the abdomen. Where damage is found, you can check on the chinch bugs by getting down and parting the grass and watching for the pest, or you can take a gallon of water with a tablespoon of lemon soap and pour it over the area between injured and good grass and watch for the little pests to come up out of the grass. Figure 6.
7. Spider mites — These little pest are also a more serious pest during the hot, dry weather. Their piercing, sucking mouthparts are small, and their shallow feeding on the plant tissue causes a stippling effect on the foliage. This gives the leaf a yellowish cast that turns gray as feeding increases. This reduces photosynthesis and can cause both early leaf drop and abortion of the fruit on plants. They are not actually insects but spiders. They have eight legs and can spin a web or layers of silk that allow them to move about the plants with ease. There are two primary spider mites here – the two-spotted spider mite and the European red spider mite. Both create the same problems but are very different. The two-spotted spider mite is off-white with two dark spots on either side of the abdomen. This color will vary with the host, but the spots remain. It can be pink or red on tomatoes or strawberries or very dark on eggplants. The eggs are pearly white. The European red spider mite is bright red with white hairs on the body, and the area around the base of the hairs is white. The eggs are bright red with a white setae or hair on top. These pests can be managed but not controlled with an insecticide. Miticides or oils like ultra fine oil can be used to control these populations. If oil used alone it will require two to three application 7 to 10 days apart to get the job done. With a miticide and oil, one spray may be sufficient. The earlier the population is detected and treated, the easier it is to manage. Lady beetles and other predators will feed on these pests, so check before spraying. Figure 7.
8. Broad mites — This mite develops on a wide variety of plant material, including begonia, impatiens, gerbera, ivy, dahlia, bean, schefflera, citrus and pittosporum. This mite is close to the cyclamen mite and is hard to separate without magnification. The broad mite is not restricted to the underside of the leaves like cyclamen and typically produces bronzing and crinkling of the foliage. Infestations on some plants produce sudden stunting, twisting and crinkling of the young foliage followed by blister or sudden dieback. The injury is often associated with herbicide damage. Flowers will abort, and on citrus russeting of the skin of the fruit is common. Under ideal conditions, the life cycle can be as short as a week. Miticide sprays with ultra fine oil can control this pest. Some success has been shown using Sevin sprays when early populations are first noted. On citrus, that is shortly after bloom on trees infested the previous year. Figure 8.
Until next month,
Dale
[Image: Pine and Grape Colaspsis]
[Image: larva, pupa and adult Colorado potato beetle]
[Image: Different leaf miners in Louisiana]
[Image: Tortoise beetle and larva.]
[Image: Variance in color of Salt Marsh caterpillars.] | [Image: Nymphs and adult chinch bugs.]
[Image: Two spider mites.]
[Image: Eggs, injury and adult broad mite.]
|