My tomato leaves are curling, but have no spots

Q. My tomato leaves are changing. They look like they are curling, and are now misshaped. Ihe middle vein is getting bigger and the leaves are puckering. I don't have any that are turning brown or have spots. My husband said I over-fertilized them. I did treat them with Actinovate for blight when I planted them, and did again just after I noticed the leaves changing. Can you help my poor tomatoes?

A. The curling you describe could be either herbicide damage or curly top virus.

Herbicide damage. Curled or stunted leaves can indicate exposure to an herbicide.

Herbicide effects mimic the plant hormone auxin and can also cause abnormal stem growth and leaf distortion.

If your tomato patch is near your yard or a neighbor’s, perhaps a weed-and-feed product, weed control, or other herbicide was applied and drifted. Mist often affects tomato plants.

Most of the time herbicide damage is not fatal. If you (or your neighbor, such as the case might be) stop applying herbicides, soon your plant will recover and re-strengthen.

Curly top. This disease, caused by a virus, affects first leaves and then the entire plant. Leaves become curled, puckered, and then yellow. They twist upward. Fruit may wrinkle. It may appear as if the entire plant is wilting. You can determine whether or not water stress is the problem simply by watering your plant.

Curly top is spread by the beet leaf hopper and white flies. Unfortunately, there is no organic or inorganic treatment, nor are there many tomato varieties that are truly resistant. Remove and destroy affected plants as soon as possible. You can prevent future curly top infections by controlling leaf hoppers and white flies.

Over-fertilizing? As far as over-fertilizing goes, usually leaves get brown spots (burns), yellow, or drop. Or, when over-fertilized with a fertilizer with too much nitrogen, then tomato plants will have beautiful foliage but few, if any, blossoms or fruit (nitrogen stimulates leaf growth).

Actinovate is a reputable biological fungicide. It helps prevent early blight, late blight, and other fungi that affect tomatoes. So it's unlikely that Actinovate would cause curly leaves on your tomatoes.

Hope this helps!

Good Luck and Happy Gardening!
Your friends at Tomato Dirt