A garden is a haven for many insects. Some insects are beneficial to plants while others are harmful. It is important to keep most of the good insects and get rid of the bad ones, especially in a vegetable garden. Fortunately, you do not have to look further to do just that since beneficial insects that are predatory help vegetable gardens thrive by eating or killing non-beneficial insects.
Beneficial insects and spiders are predatory to other bugs that are harmful to plants. They eat aphids, caterpillars and other soft insects that feed on vegetables.
Assassin bugs, parasitic wasps, ground beetles and praying mantises are examples of predatory bugs that feed on body fluids of caterpillars, grubs and other insects. Aside from eating caterpillars, praying mantises also eat grasshoppers and bees.
Big-eyed bugs and pirate bugs feed on insect eggs, other soft-bodied insects while lacewings and ladybugs feed on aphids and smaller, soft-bodied insects.
Predatory wasps sting and collect insects to build their nests as well as help in pollination. Honeybees, may not be predatory, but they help plants through pollination.
All spiders are beneficial to plants. Some are nocturnal and feed on all insects and other arthropods. The common spiders found in a vegetable garden are striped lynx, celer crab, winter, star bellied orb weaver, gray-dotted, long-jawed orb weaver, ridge-faced crab and black and white jumping spiders.
Many insects chew on vegetables in order to survive and develop, causing extensive damages on the leaves and fruits of plants. Some insects have mouthparts that can cut and tear off plant tissue. These insects often leave holes in the plant tissue or foliage. They also deposit fecal materials on plants and soil that may be brown, black or green in color and resemble small flecks or balls. Examples include caterpillars and grasshoppers that feed on fruit or leaves. Garden webworm, pickleworm, cabbage worm, melon worm, diamond black moth, fall army worm, pepper weevil, carrot weevil, flea beetle and Texas leaf-cutting ants are all chewing insects.
Other non-beneficial insects cause harm on plants by inserting their mouthparts into the plant tissue and sucking liquids from the plants. Sucking insects leave their feces behind, which are sticky liquid (honeydew) in consistency that builds up on leaves or fruits. These shiny residues may support the growth of a black or gray sooty mold, which can damage foliage that can often turn yellow to brown in color or become deformed. Examples include stink bugs, sharpshooters, sweet potato whitefly, greenhouse whitefly, squash bug, leaffooted bugs, thrips, leaphoppers, mites and aphids.
Insects considered soil insects cut plants at or slightly below the ground level. They feed on roots, tubers and underground stems. Soil insects may attack and damage many different vegetables and fruits that come in contact with soils such as strawberries. Examples include granulate cutworms, mole crickets, southern corn rootworm, pillbugs, sawbugs, sweet potato weevil, white grubs and wireworms.