Tomato worms are pests with which nearly every gardener who grows tomatoes must deal. There are different species of worms, all of which are actually caterpillars or larvae of various insect species. At best, these pests are a nuisance and, at worst, can be catastrophically destructive. Organic controls and techniques exist for home and commercial gardeners to control these pests.
Types of Tomato Worms
There are many types of tomato worms, but the most common and most destructive are the fruitworm, hornworm, cutworm, cabbage looper and pinworm. The tomato fruitworm is a caterpillar about 2 inches long, somewhat hairy, and it may vary widely in colour or markings, from cream coloured or yellow-green to reddish, green or brown with pale stripes and/or black spots. The tomato hornworm is a large caterpillar, 3 to 4 inches long, bright green with seven white diagonal stripes and a rear-projecting red or black horn. The tomato cutworm is a fat, grey, brown or black caterpillar about 2 inches long. It is active at night. The cabbage looper is a 1-inch green caterpillar with longitudinal stripes of white and is usually found on the underside of tomato leaves. The tomato pinworm is a small green, grey or yellow caterpillar about 1/3-inch long with purple spots. This pest folds leaves over and webs them together.
Do-it Yourself Controls
Tomato hornworms, being so large, are often controlled simply by removing them by hand. Dropping them in a container of very soapy water will kill them. Sprinkling corn meal around the tomato plants will also kill hornworms. They eat it, but cannot digest it, and they burst. Some types of tomato worms can be controlled with a simple spray of soapy water, made with one-quarter cup of biodegradeable soap with a gallon of water. Rinse the plants an hour later to prevent leaf burn. A solution of four or five puréed very hot chilli peppers mixed with water will also deter tomato worms. Or try a solution of one-quarter cup of oil mixed with water.
Dipel dust and rotenone will both control hornworms, cutworms, cabbage loopers, tomato fruitworms and pinworms. Neem oil-based products work well on cabbage loopers and cutworms. Spinosad-based insecticides are effective for all tomato worms. However, spinosad is different from other treatments in that the pest must eat a treated plant part to be effective. Other controls kill the worms on contact.
Prevention of pest infestation is one of the most favourable techniques for controlling tomato worms. Rotate crops by planting tomatoes in a different area of your garden each year. This helps control tomato worms because many overwinter in the ground near the tomato plants they infested the previous year. Roto-tilling in the fall will kill many overwintering tomato worms. The best tactic for dealing with cutworms is to place a collar of stiff paper or an old tin can around the base of the tomato plant. The reason for this is that once cutworms attack a plant, they can kill it overnight by cutting the stem completely. Companion planting your tomatoes with garlic can help repel many pests.
A variety of insects can help control tomato worms. Ladybirds, praying mantises and predatory wasps prey on tomato worms and other garden pests. Toads, frogs and many species of birds will also feed on the tomato worms.