Well, summer is here, and we are seeing some different pests to start it off.
1. Convict caterpillars – This caterpillar is usually found only in the swamps and nearby areas feeding on spider lilies. Every few years we get high populations, and they find amaryllis and a few other lilies planted in the yard. They can eat all of the foliage on the plants to the ground and then feed on neighboring plants to complete maturity. There are up to seven generations a year, and the larva pupate in loose soil near the host. The adults have rosy-pink forewings, spotted with orange along the veins, with a black body and gray hind wing. The larvae are brightly colored with black and white or creamy stripes and bright orange heads, legs and posteriors. The head and tail end each have two eye-like black spots making the posterior end much like the head. The adults are called Spanish moths. Figure 1.
2. Magnolia scales – Specific to magnolias, this scale can infest and reproduce very quickly. There is only one generation a year, but the secretion of honeydew promotes the development of sooty mold. High populations may cause die back on branches and stunting of plant growth. The crawlers are live born, and as they settle and begin feeding they excrete a yellowish white wax that covers the body. This waxy layer makes it hard to control at times. Sprays can be used but must contain a spreader sticker or oil to adhere to the scale. The Japanese magnolias are the primary trees infested. An option to spraying on small trees and shrubs is to paint a slurry of Orthene or Merit (4 parts wettable powder chemical to one part water) on the terminals of infested stems. Wipe off six inches of the infested terminal to remove dirt and other organic materials, then paint the entire terminal with the slurry. This allows the plant to absorb the insecticide into the cambial tissue, and since it transports the food to the roots, it carries the insecticide through the feeding site of the scale. This provides for a more concentrated form of the insecticide reaching the scale. Figure 2.
3. Horse flies and deer flies – Biting flies can be serious pests during the summer months. This year with the rains, we seem to have a large population. They are an aggravation around swimming pools and at outdoor activities like picnics, fishing or hiking. They are difficult to manage, but the use of repellents and wearing light-colored clothes can provide some relief. Eggs are laid in masses of 100 to 1000 in areas that overhang water or moist areas. The larvae of horse flies are carnivorous and cannibalistic, feeding on insect larvae, snails, earthworms, etc., while deerflies feed on decaying organic matter. Development varies from 3 months to 3 years. Adults live about 3 to 4 weeks. They have tearing, lapping mouth parts. Both sexes feed on nectar, but the females need a blood meal to lay eggs. Although primarily daytime feeders, some are attracted to lights at night. Figure 3.
4. Two-lined spittlebug – Adults are similar to leafhoppers, only wider. They are 3/8 inch long with black or brown wings with two bright orange-red lines across the forewings. The immatures develop in a spittle mass on the rhizoid and have white, yellow or orange bodies with brown heads and red eyes. They are piercing, sucking feeders on grasses, ornamental plants and some crops and weeds. The immatures develop in a frothy mass going through 4 instars, requiring about a month. There are 2 generations per year. They can be controlled when necessary with pyrethroids or systemics. Figure 4.
5. Silverfish and firebrats - All members of this family, Thysanura, have teardrop-shaped bodies ending in 3 long, bristlelike appendages. They are domestic species that inhabit buildings. They feed on starchy substances. In libraries they feed on the starch in books, bindings and labels, and in homes they will feed on starched curtains, linens, silks and the starch paste in wallpaper. In stores they feed on paper, vegetables and foods that contain starch. Silverfish are gray or silvery in color, and the firebrat is tan or brown with dark markings. Both have incomplete, metamorphosis with each stage looking like the adult. Silverfish like cool, damp areas while the firebrat likes a warm, humid environment. Both are very active and fast runners. They are primarily night movers, hiding in cracks and crevices during the day. Pyrethroids do a good job of managing populations. Figure 5.
6. Lace bugs: azalea and lantana – The azalea lace bug has lacy wings with brown and black markings and light brown legs and antenna. The lantana lace bug is a small, brown, elongated oval lace bug without the extended pronotum over the head as many other lace bugs have. The immatures are very different from the adults. The azalea nymphs are colorless at birth but soon turn black, while the lantana nymphs are dull in color. Both have a series of spines around the abdomen. Both are piercing, sucking feeders, and their feeding causes a stippling of the foliage of the host and gives the foliage a gray-to-bleached cast when feeding is heavy. Heavy feeding can cause premature leaf drop. Eggs are deposited in the underside of the leaf tissue along the main or secondary veins. Azalea lace bug eggs are deposited singularly, and the latana lace bug deposits them in clusters of 10 to 30. Signs of infestations are the fecal deposits on the underside of the foliage and the foliage discoloration. Treatments with Orthene, Merit or Cygon can manage these populations. Before spraying, check for adults or immatures by shaking the branches of the plants against a light sheet of paper or checking the underside of the foliage. There are 3 to 4 generations per year. They are fed on by egg parasites, lacewing larvae, assassin bugs, spiders and predaceous mites. Figures 6 and 7.
7. Cigarette and drugstore beetles – These two beetles are the same size, 1/8 inch. They are brown in color. They are identified by the antenna, which is serrated in the cigarette beetle and clubbed in the drugstore beetle. The forewings, elytra, are smooth in the cigarette beetle while the drugstore beetle has a series of punctures in rows, giving the elytra a ridged appearance. Both infest a variety of dry foods, spices, tobacco and insect specimens in collections. The cigarette beetle has 3 to 6 overlapping generations a year, which require 30 to 90 days to complete. The drugstore beetle has 1 to 4 generations per year, requiring 7 months but ranging from 60 to 210 days. Both beetles fly and are attracted to light. Management can be accomplished by checking the expiration date on dry foods and spices and purchasing only the freshest products. Once infested, find the source and dispose of these products and treat with a pyrethroid in cracks and crevices. Figure 8.
8. Bed bugs – This bug gets its name from its close association with humans sleeping in beds where it often seeks refuge during the daylight, emerging at night to feed on the bed occupants. In recent years this pest has become a more serious pest. The female lays 1-5 eggs per day in cracks or rough surfaces. The nymphs go through 5 instars and require a blood meal for each molt. Development requires 21 days and is temperature dependent. Although colorless, they become reddish after taking a blood meal. They like to hide in cracks and crevices during the daytime and come out at night. Infestations can be moved via used furniture or belongings from someone living in an infested area. Adults can survive for 6 to 7 months. Infestations have been found in boats, trains, buses, airplanes and movie theaters. Besides the characteristic sweet obnoxious odor, the primary indicators are small reddish brown fecal spots here and there on surfaces. Infestations can be managed with good sanitation and the application of a pyrethroid. Visit the LSU AgCenter Web site for additional information. Figure 9.
| | Convict caterpillar and adult moth. |
| | Magnolia scale infestation. |
| | Two lined spittle bug and nymph. |
| | ssilver fish and firebrat. |
| | | Azalae lace bug showing lacy design on wings. |
| | Lantana lace bug and nymnph |
| | Two pests of pantry products. |
|