Agents;
We have discussed numerous pests that can be found in and around the homes and fields. Recently we have had several beneficial insects sent in for identification. Here are some of the more common beneficial insects we see that help to manage the pest problems.
1. Tiger beetles – These small brightly colored beetles are predatory in both the adult and larval stages. Both posses a very large pair of mandibles used to grab, hold and chew whatever they catch. The adults lay eggs in sandy soils and the larva, a slender white larva with a large brown head and mandibles, burrows into the soil. The holes in the soil are about pencil size with the opening slightly oval in shape. The larva rests its open mandibles on the edge of the hole with the head level with the soil line and only the eyes extending above the soil surface. Any unsuspecting insect that passes by is susceptible to capture with the large mandibles and is pulled into the hole and eaten. The larva has a series of hooks on the fifth abdominal segment, which help prevent it from being pulled out of the tunnel when it catches large prey. The adults are brightly colored in iridescent greens and blues or have a definite pattern with white. They are quick runners and will fly when pressured but only short distances, turning and facing their pursuers. They are predators feeding on a variety of small insects. Figure 1.
2. Lace wings (green and brown) – The green lacewings are greenish in color with copper-colored eyes. They commonly occur in grass and weeds and on the foliage of trees and shrubs. The larvae are predaceous and possess an elongate pair of cycle-like mandibles. These hollow mandibles are used to suck the bodily fluids from their host, usually soft-bodied insects like aphids, mites or small caterpillars. The brown lacewing larva has similar mouth parts but is smaller. It glues pieces of lichen and other debris to its body for protection and appears to be a walking trash pile when observed. The larvae are all predaceous as are most of the adults. The adults of the brown and green lacewings are predaceous, feeding on small soft-bodied insects and mites. The green lace wing lays its eggs on the end of a stalk to prevent predation by the other larvae, but the brown lays it eggs on plants without stalks. Figure 2.
3. Ant lions – The adults resemble damsel flies except for their long clubbed antenna, softer bodies and their feeble flight. The adults are attracted to lights. The larvae, sometimes called doodle-bugs, live in the soil. The most common species digs a funnel-shaped pitfall trap in the sandy soils, and the larva sits at the bottom with mandibles open for the next insect to fall into its trap. The larvae are hard to catch as they move forward and backward with equal speed. When disturbed they play dead, and because of the covering of dust or dirt, they are hard to see. Figure 3.
4. Dragon flies and damsel flies – This is a very large and very colorful group of insects. The adults are excellent fliers, and the immature stages are aquatic. All stages are predaceous and feed of other organisms. The immature are called nymphs and have a prehensile labium capable of extending out to catch unsuspecting hosts. The immature can be cannibalistic and feed on other nymphs as well as other insects and small fish or minnows. The adults are excellent flyers and can dart about very quickly to catch food on the wing. Occasionally beekeepers who have hives near bodies of water have to move them to reduce the predation from the larger dragonflies on the hives. Figure 4.
5. Earwigs – These insects are primarily night feeders except when disturbed by turning over a rock, log or loose bark. Most feed on dead or decaying vegetable matter, but some are predaceous. They have short wings, which are folded up over the upper third of the abdomen. The wing covers are usually orangey brown against a black body. The adults posses a pair of forceps-like appendages at the end of the abdomen, which are used in mating and in holding live food. The pinchers may grab you when holding them, but only the larger male earwigs can inflict a painful pinch. Some possess the ability to emit or squirt a foul-smelling fluid when disturbed as a means of defense. Some winged forms are good fliers while others rarely fly. Figure 5.
6. Assassin bugs – This is a very large group of predaceous insects. They are commonly blackish or brownish in color, but some are brightly colored. Most species are predaceous on other insects, but a few are bloodsucking and frequently bite people. Most species will inflict a painful bite if carelessly handled. One of the largest and most easily recognized is the wheel bug. This large, brownish tan assassin bug has a semicircular crest on the pronotum with small teeth resembling a cogwheel. The other more common species is the masked hunter. About 1/3 the size of the wheel bugs, it is brightly colored orange and blue. The early immature of this predator resembles the early instars of the leaf footed bug. The two can be separated by checking the number of segments in the beak -- 3 for the good guy and 4 for the pest. In the third instar the leaf footed bugs’ hind leg begins to flatten out and expand, giving the leaf footed appearance. Figure 6.
7. Lady beetles – Numerous species of various sizes and colors can be found in Louisiana. The color varies from solid black to pink and black or gray and black and many colors in between. The more predominant colors are red and black. They vary in size from the larger Asian lady beetle that can be as much of a pest as a beneficial to the very small -- about the size of the head of a pin. Both the adults and larvae are predaceous and feed on soft-bodied insects such as scales, aphids and mites. The larvae are usually multicolored with hairs, setae or spines, and some are covered with waxy filaments that cause them to be mistaken for mealy bugs. They are effective predators but are often mistaken for pests by unknowing individuals and sprayed, releasing the pest population to continue to injure the plants. Figures 7 and 8.
8. Syrphid flies – Flower flies, sweat flies or hover flies are very common and vary greatly in habitat and appearance. Many are brightly colored in shades of orange or green and brown and resemble bees or wasps. They may resemble honeybees, bumble bees and various wasps, but none of them bite or sting. Not all are predaceous. Some live in decaying vegetation, rotting wood or polluted aquatic habitats, and some live in the nests of social insects -- termites, ants and bees. The rat tail maggot is an example of one that lives in aquatic habitats. Those that feed on aphids and small insects are light green or gray in color and resemble a typical maggot. The adults are orange and tan colored and vary greatly in size. They are usually observed hovering about as you work in the yard, occasionally landing on your arm or leg apparently to drink from the sweat on you. They are often observed on plants with aphid infestation depositing eggs near that host. The adults are not predaceous. Figure 9.
9. Robber flies – This is a very large group of flies that are found in a variety of habitats. The adults are predaceous and feed on a number of insects, including bees, wasps, dragonflies, grasshoppers, other flies and small butterflies. They will often attack insects their size or larger and always capture their prey on the wing. The larger robber flies can inflict a painful bite if mishandled. Most of the robber flies are slender and elongate; others are stout-bodied and hairy, resembling bumble bees or other bees or wasps. Yet others are very slender and resemble damsel flies. The larvae live in the soil and are predatory on other insect larvae. Figure 10.
10. Wasps – Wasps are excellent predators, feeding on many soft-bodied insects and spiders. Depending on the wasp, the host range may be very broad or very specific. Mud daubers prey entirely on spiders. Break open a mud nest and observe the array of spiders collected as food for the next generation. Yellow jackets and hornets will feed on just about anything they can catch or steal. They can be observed trying to take fish or game when you are cleaning them, and they will forage on over ripe fruit and scraps left on a picnic table or trash can. Paper wasp feed on many soft bodied insects and feed their larvae with them. The Mason or potter wasp provisions its nest with caterpillars. All do a great job of predation but occasionally build their nests in inconvenient locations which require removal. The use of yellow lights around the outside of the home will reduce the population nesting near the house. These lights reduce the insect populations, which reduce the spider populations, which reduce the wasp populations.
Until next month,
Dale