Tomatoes are among of the most common plants grown in vegetable and fruit gardens. They are however, susceptible to several insects. Stinkbugs, horn bugs, whiteflies, psyllids, aphids and flea beetles often are the culprits, with yellow, sappy, brown leaves and damaged fruits as their evidence. If you are having problems with these or any other bugs, don't give up. With proper identification, treatment and prevention, you can continue to grow tomatoes and reap a successful if less plentiful harvest.
Identify the pests so you can properly treat them. For example, a hornbug is 3-inch long caterpillar with a "horn" at its back end. Whitefly nymphs are small, white and usually on the undersides of tomato leaves. Take a bug and damaged leaf or fruit to a nursery or local extension office for identification and treatment recommendations.
Treat the bugs. Apply bacillus thuringiensis (Bt), insecticidal soaps, sulfur or pesticides for bugs that affect tomato plants. Apply under the leaves as well as on top. Follow the labels' instructions for dosages. For smaller infestations, pick the bugs off with tweezers in the morning and put them in a bucket of soapy water.
Pick off damaged fruit so the plant can focus its energy on growing new tomatoes.
Remove weeds and mulch. Clean up any debris to discourage the bugs from over-wintering in the soil. Plant the tomatoes next year in an area where they have not been planted in the last four years.