What’s wrong with my ailing tomatoes?

Published 9:17 am Wednesday, June 29, 2011

It never fails; we plant our tomatoes, water them, feed them, do everything we can to ensure their survival, and then “something” happens.

This is the time of year when that “something” starts to occur. I have received numerous calls about tomatoes already this year, and everyone wants to know “what’s wrong with my tomatoes?”

Unfortunately, there is no one right answer. There are several disorders, insects and diseases that can affect tomatoes during summer. Below are a few common problems, what causes them, and in some cases, what you can do about it.

• Symptoms—Overall poor growth, wilting, stunting and chocolate-brown spots on the leaves; if fruit is present, there may be circular discolorations on the surface.

Possible diagnosis—Tomato spotted wilt virus

Cause—This virus is transmitted when thrips (very tiny insects) feed on plants

Management—Unfortunately, there is no cure once your plants are infected; the key is prevention. Resistant varieties of tomato are your best bet, but insecticides to manage thrips will help, too.

• Symptoms—Leaves folding and curling, but they do not appear misshapen or distorted

Possible diagnosis—Plant response to environmental conditions

Cause—All plants lose moisture during a natural process known as transpiration. When it is excessively hot outside, plants will transpire more, and will therefore lose more moisture. Folding leaves to prevent moisture loss is a natural defense mechanism for the plant.

Treatment—Make sure to irrigate tomato plants during periods of dry weather. Remember, they will require more moisture when it’s excessively hot.

• Symptoms—Leaves twisted, elongated, misshapen, or deformed

Possible diagnosis—Herbicide damage

Cause—Tomatoes are very sensitive to herbicides. When herbicides are used in close proximity, some of these symptoms may occur. They also can occur from drift or use of straw mulch containing traces of herbicides.


• Symptoms—Missing leaves, almost as if cut off; leaves may be chewed; may also see significant defoliation of the plant

Possible diagnosis—Hornworms

Treatment—Remove worms by hand and destroy; there are some insecticides that might be effective.

• Symptoms—Sudden wilting of the entire plant; may look as though it is water deprived, even if it has received adequate moisture; examination of the plant stem near the soil line may show a white, moldy-looking growth and small brown structures resembling mustard seeds

Possible diagnosis—Southern blight

Treatment—None currently available

• Symptoms—Cloudy, yellowish spots on ripening tomatoes; area underneath these spots will be corky

Possible diagnosis—Stink bugs

Cause— Stink bugs feed by inserting their mouthparts into the tomato and sucking out the juices

Treatment—Requires an insecticide application

• Symptoms—Rotten spots on bottom of fruit

Possible diagnosis—Blossom end rot

Cause—Can be related to a calcium deficiency and adequate water

Treatment—A soil sample will tell you if there is enough calcium available in the soil. Ensure even watering by irrigating during dry periods.

Unfortunately, these are just a few of the problems we can see in tomatoes. There are many other insects and diseases that can affect a crop.

JANET SPENCER is the agricultural and natural resources extension agent in Isle of Wight County. She can be reached at jaashle2@vt.edu.