Managing Common Tomato Problems

Cracked Fruits: When tomato fruits crack open, the problem is usually that the plants are getting too much moisture and nutrients. Cut back on the water and fertilizer a bit and look for cracking-resistant varieties.

Fruits Have Dry, Dark Areas at the Ends: Dry, dark spots on the end of the fruits appear because of blossom-end rot, a condition caused by hot, dry conditions or fluctuating moisture levels. Keep plants well watered during hot weather and make sure they're watered consistently.

Old Leaves Have Brown of Black Spots: Early blight is a common disease that disfigures old leaves. Remove the leaves as soon as you see spots form; this may prevent it from spreading to the rest of the plant. Spreading mulch over the soil and keeping the leaves dry can also be effective preventive measures. Spraying with fungicide can help, too, but only if you spray before the disease takes hold. Early blight cannot be cured.

Old Leaves Have Pale Green Spots That Look Water-Soaked: This is late blight. Prevent the common fungal disease by removing infected leaves as soon as you see spots form. Other prevention techniques are to spread mulch over the soil, keep the leaves dry, and spraying with fungicide before the disease gets too bad. Late blight cannot be cured.

Leaves Turn Yellow Before Wilting and Turning Brown: Two common diseases -- verticillium and fusarium -- cause this symptom. Both are preventable. Remove infected leaves as soon as you see spots form -- this can prevent it from spreading through the entire plant. Also try spreading mulch over the soil, keeping the foliage dry, or as a last result, spraying with fungicide before the disease takes hold. Fusarium and verticillium cannot be cured.

Large Green Caterpillars That Eat the Foliage: Tomato hornworms can rapidly devour your prized tomato plants. Organic options are to squash or drop the caterpillars into a bucket of soapy water or to spray with Bacillus thuringiensis, a bacterium that attacks and kills caterpillars. Note: Several species of wasp will lay their eggs on the caterpillars. If you see a hornworm with the eggs, don't bother killing it. The wasps are already doing it for you.