In part two of tomato problems, we take a closer look at foliage and what it can tell you about what might be wrong and then how to treat it. 

Symptom: Leaves roll upward and are firm and leathery, but with no yellowing or stunting. Leaves on the sunny side of staked plants may often curl, while those on the shady side do not.

Problem: Common growth, no harm to plant development or fruit production. Too much leaf pruning, sucker removal, or overly wet soil may pro­mote it.

Solution: Plant on well-drained soil. Do not cultivate deeply near the plants, and avoid extremely close pruning.

Symptom: Roll upward and twist, become stiff and leathery, yellowed, stunted. Veins on the underside turn purple.

Problem: Curly top, western yellow blight. Transmitted by leafhopper from weeds.

Solution: Use resistant varieties. Destroy infected plants. 

Symptom: Yellow and green mottling, crinkled, and smaller than normal, shoestring appearance.

Problem: Mosaic viruses. Transmitted from weeds and flowers, aphids, cucumber beetles.

Solution: Wash hands with soap and water before handling plants. Do not smoke or handle tobacco before or while handling plants. Remove and destroy infected plants.

Symptom: Numerous small dark brown circular spots on young leaves, becoming bronzed and withered; older foliage is yellowed. Dark brown spots or streaks on stems near tips.

Problem: Spotted wilt. Spread by thrips from weeds and ornamentals.

Solution: Keep separate from vulnerable vegetables like lettuce, celery, spinach, peppers, and potatoes. 

Symptom: Yellowing, wilting, dying of lower leaves progressively up the plant. Initially, it often affects only one side of the plant. Brown streaks in tissue of the lower stem when split lengthwise. Produce few fruit which usually decay and drop before ripening.

Problem: Verticillium or fusarium wilts.

Solution: Plant resistant varieties. Use clean soil. Avoid areas previously planted with toma­toes, peppers, eggplant, potatoes, or cucurbits. Destroy infected plants.

Symptom: Distorted, cupped, or curled, ragged at edges, curved downward. Light-colored veins appear parallel.

Problem: Hormone-type herbicides.

Solution: Use extreme care when using herbicides. Plants may outgrow damage if given good cultural care.

Symptom: Irregular greenish-black water-soaked patches on older leaves which enlarge and may show a white, downy growth on the surface. Fruits develop a gray, green spot which becomes brown and wrinkled or corrugated; may become mushy.

Problem: Late blight fungus.

Solution: Prevalent in mild, moist weather. Hot, dry weather will slow or stop the advance of disease.

Symptom: Dark areas of dead tissue surrounded by yellow on oldest leaves.

Problem: Anthracnose, a soil-borne fungus disease.

Solution: Avoid handling wet plants or planting in poorly-drained soil. Rotate to new soil each year. Remove and destroy infected plants or plant parts after harvest.

Symptom: Many tiny round holes, leaves may be so riddled that they turn brown and wilt.

Problem: Flea beetles.

Solution: A few holes are not damaging. Most damage occurs during the first warm weather of spring, when plants are small. Apply garlic spray.

Symptom: Eaten or chewed, partially or entirely.

Problem: Hornworm.

Solution: If the worm is carrying white pupae, let it be -- it's the victim of a parasitic braconid wasp and should be left to nurture a new brood of beneficials. Remove worms by hand and destroy (sprinkling water on plants will make them wriggle, making them more visible and easy to pick). Spray with Bt. Release trichogramma wasps.  

Symptom: Greasy appearance becoming bronzed and stippled, webbing and "moving dust" on undersides of leaves or in leaf axils. The plant appears to dry out from the ground up. Leaves turn brown and paper-like but do not wilt.

Problem: Mites.

Solution: Thrive in hot, dry weather. Wash down plants, especially undersides of leaves. Use garden sulfur according to label directions.

Photo by Jessica Yarger