Identifying Texas Vegetable Garden Insect Pests

Sometimes it seems to vegetable gardeners in Texas that the insect world is out to get them. Just when plants appear to be thriving and getting ready for a bumper crop of tomatoes, peppers, bean, or squash, insects attack and destroy the plants. Before spraying every vegetable plant with toxic chemicals, a little detective work to identify the culprit helps control the bad guys while protecting the beneficial insects.

Types of Insects that Damage Texas Vegetable Gardens

Entomologists place insects into the phylum Arthropoda and the class Insecta. Insects, under this classification, have three pairs of legs, three body sections — head, thorax and abdomen — and one pair of antennae. Insects have external mouthparts — chewing or sucking — that leave telltale clues about the type of insect damaging vegetable plants.

Insects with chewing mouthparts bite leaves or fruit and tear off pieces for consumption. These insects leave holes, strip leaves, or scrape plant tissue. Caterpillars are an example of a chewing insect. Insects that consume only liquids such as nectar or plant fluids have a piercing-sucking mouth. These types of insects leave a damage signature that includes spotting, curling and wilting of plant leaves or stems.

According to the University of Missouri Extension Service, correctly classifying plant damage as a function of the types of insect mouthparts provides direction for control. ‚”If an insect has chewing mouthparts, it will ingest a pesticide that is present on the surface of the plant…To kill insects with piercing-sucking mouthparts; an insecticide must have contact toxicity ‚Äî meaning it kills by just contacting the insect.”

Identify Vegetable Garden Insect Pests

Using plant damage as a guide to classification provides useful guesses. However, the best way to identify garden pests correctly involves matching pictures and descriptions along with knowledge about which insects tend to attack specific garden vegetables. A Texas A&M University extension service provides detailed information and pictures to aid insect classification by crop attacked.

For example, bean plants often sustain damage from granulate cutworm, aphids, thrips, cabbage loopers and stink bugs. Tomato plants are favorite victims of those insects plus tomato pinworm, tomato hornworm, armyworm, leafminers, and two-spotted mites. Each entry on the Texas A&M insect website includes a description of the insect, a picture, and a detailed description of the visible damage done to the plant. The integrated pest management (IPM database) link at the bottom of each insect page suggests ways to control that insect on your Texas vegetable garden plants.

Whether a gardener chooses chemical or organic insect control, it is essential to classify the pest correctly, select and apply control as soon as possible. The greater the infestation, the more damage done and the more difficult it is to save the plants and keep them productive. Correct identification also keeps a Texas gardener from accidentally killing beneficial insects.