By Suzanne DeJohn

Insect Control Rule Number 1: Never spray an insecticide until you've identified the culprit. Not all insects are pests -- many are beneficial, most are benign. Don't assume that any insect crawling around on a plant is there to cause trouble. For example, ants on peony buds are harmless.

  • Tomato hornworm feasting on a tomato leaf.
  • Tools and Materials

    • notebook
    • magnifying glass
    • camera
    • jar (for collecting samples)
    • insect field guide

    If you suspect an insect is causing problems, examine the plant. Check the leaves, top and bottom, looking for insects, caterpillars, and egg masses. As you touch the leaves, watch for scurrying or flying insects. Jot down notes, take a photo, or collect a sample so you can research the possible culprits using a field guide or gardening reference. Wait to spray until you've made a positive ID. Many insecticides will kill not only pests but also beneficial insects, including predatory insects that eat the pests and pollinators like honeybees.

    If a plant is struggling, consider non-pest causes first. For example, if you see a wilted plant, check soil moisture. Gardeners sometimes mistake symptoms of nutritional deficiencies -- yellowing leaves, stunting, weak growth, poor production -- as indications of pests. If you see symptoms like these, consider testing your soil nutrients and pH levels.

    Types of Insect Pests

    Entomologists (insect specialists) often categorize insects by how they feed.

    Chewing insects eat leaves. Symptoms include holes, ragged edges, and "skeletonizing" -- eating the tissue between leaf veins. Examples include weevils, caterpillars, flea beetles, and Japanese beetles. Look for the telltale frass (excrement) of the larger of these pests.

    Sucking insects pierce a hole in plant tissue and suck out the fluids. Signs include stippling on foliage or silvery bronze leaves and discolored blooms. Examples include spider mites, aphids, thrips, and leafhoppers. These pests often leave behind moltings -- the outer skin they shed as they grow.

    Other insects, such as wireworms, feed on roots. Cutworms feed at ground level, girdling young seedlings.

    Tips

    Once you've identified that you indeed do have a pest problem, determine whether control is really necessary. Is the damage located on the leaves of a plant you'll be harvesting in a week or two? Control measures may not be warranted. However, many pests multiply quickly so keep a close eye on pest populations.

    Once you've identified the pest, research its life cycle and habits. Some pests, such as leaf miners that tunnel into plant tissue, will not be affected by sprays. Controls will be more effective if you catch the insect in the most vulnerable part of its life cycle.

    Together with Victory Seed Company:
    Victory Seed Company Logo Victory Seed Company has all the seeds you want for your best garden in 2024.

    For 25 years, the family-owned Victory Seed Company has provided the highest quality vegetable, herb and flower seeds to families across the country. We are passionate about providing you the best seeds available that give excellent germination, robust plants, and the harvest you want. With a catalog of over a thousand varieties, we have everything, and our prices are the kinds that we'd want to pay. We have hundreds of yesterday's heirloom vegetables, as well as today's award winning hybrid selections. Get to know us by visiting our website and browsing through our online vegetable seed catalog.

    Today's site banner is by SongofJoy and is called "Blue Pansies"

    This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.