Stem has gone brown halfway up

by Mrs. P
(Kent, England)

Q. My tomatoes are grown in a greenhouse along with pepper plants. The stems have gone completely brown about half way up the stem, with a brown patch about 2 inches long. Some leaves have gone brown as well. Some of the tomatoes went brown. I have picked them off. Is it OK to still eat the tomatoes that are ripening?

Tomato Dirt responds ...
A. When verticillium wilt attacks a tomato plant, its stem darkens about 10-12 inches above the soil line. Leaves turn brown. Verticillium wilt can affect a tomato plant at any point in its development, but is most common during the fruit-producing stage.

Infected plants usually survive the season but are stunted. If they produce any fruit, it’s small and underdeveloped. Having said that, the fruit is edible.

Verticillium wilt is caused by a fungus, which works its way up through the plant’s roots, clogging water-conducting tissue in the stem. It spreads a toxin that wilts and spots leaves and prevents water from reaching branches and leaves, starving the plant. The fungus thrives in cool temperatures and when soil is moist and not too warm (60-75ºF).

Prevent verticillium wilt next year by destroying all plants at the end of the season. You will also want to disinfect containers you used in the greenhouse this year so the fungus doesn't spread to next season's crop.

Get more information about verticillium wilt, what causes it, and how to prevent it on this page.

Good luck and happy gardening!
Your friends at Tomato Dirt