How to Get Rid of Caterpillars on Tomato Plants

Overview

Caterpillars, specifically the tomato hornworms, are bothersome pests to tomato growers. They eat the leaves, sometimes killing the entire plant, because irreversible damage is often done even before the caterpillars or any signs of them are noticeable. This is because they blend in with the leaves and they eat them starting on their underside. For these reasons, begin the process of ridding your tomato plants of these caterpillars even before you see them or any evidence.

Step 1

Remove the plants and rototill the planting site after you are done harvesting the tomatoes. This will help with next year's crop by killing the larvae burrowed in the ground for winter. Alternatively, choose a different location to plant your tomatoes than the previous year's.

Step 2

Examine the underside of the leaves beginning in early summer -- even if you don't see any damage yet. Repeat twice a week until harvest and do so in the early morning time when the caterpillars are most likely to be out and about. Pick off the eggs and caterpillars you see and drop them into a bag or even into a bucket of soapy water to kill them. Use a magnifying glass for a better inspection, if desired.

Step 3

Spray an insecticide labeled for caterpillars and safe for plants such as tomato plants if you cannot control them manually. Usually, you must reapply every 7 to 10 days, but check the label for specific instructions. Insecticides to look into contain Bacillus thuringiensis (Bt) and are sold under such brand names as Dipel and Caterpillar Attack. Other insecticides such as Sevin and Malathion also work.