Attack of the Tomato Killers

“So far, my tomato plants are happy, but should I be on the lookout for any pests or diseases? I don’t want any critters to come between me and fresh tomato sandwiches!”

tomato plant pests and diseases - Hornworm

Tomato Hornworm – a common garden pest. (Photo courtesy of Whitney Cranshaw, Colorado State)

The tomato is the favorite of vegetable gardeners everywhere, and like most other plants, it does not come without its share of problems. Here’s how to control common tomato plant pests and diseases.

Many insect pests attack tomatoes, the most common being fruitworms and hornworms, aphids, whiteflies, and stinkbugs. Tomato fruitworms and hornworms can be controlled with sprays of Bacillus thuringiensis, a beneficial bacterium that is most effective just after eggs hatch when caterpillars are still small. Insecticidal soaps are effective for control of aphids and whiteflies if directed to the upper and lower leaf surfaces. Stinkbugs may be controlled using endosulfan, potentially spraying weekly for late-season control.

Disease control in the home garden begins by planting disease-resistant tomato varieties in well-prepared, properly fertilized soil. Disease development is favored by wet, humid conditions, so keep foliage dry by watering in the morning and use drip irrigation whenever possible. Watering deeply once or twice a week is better than shallow, frequent watering. Stake and prune plants to increase air circulation within the canopy. Begin applying a fungicide when plants are 8 to 10 inches high and repeat at 7-day intervals. Tank-mix a fixed copper compound if bacterial spot appears, and stay on a strict 7-day spray schedule. Always follow the manufacturer’s labeled directions and restrictions. It is important to completely cover the foliage to control diseases. Start the spray program at planting time. Early sprays will help prevent the spread of disease from older leaves.

By Bethany O’Rear, Regional Extension Agent, Alabama Cooperative Extension System.  Contact Bethany at bethany@aces.edu.


The Alabama Cooperative Extension System (ACES) operates as the primary outreach organization for the land-grant functions of Alabama A&M and Auburn Universities. ACES is committed to affirmative action, equal opportunity and the diversity of its workforce.  Educational programs of ACES serve all people regardless of race, color, age, sex, religion, disability, sexual orientation, or national origin.

Alabama Extension

The Alabama Cooperative Extension System operates as the primary outreach organization for the land-grant functions of Alabama A&M and Auburn Universities and answers home-gardeners' questions each week on Birmingham Gardening Today.

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