Why are my tomatoes getting black marks?

by Mae
(Palos Heights, IL)

Q. Not sure of the tomato variety. I have picked a few tomatoes off the plant earlier and they were fine, but yesterday I went to pick and the tomatoes have black marks. Some tomato tops are cracked and the black marks start there. Other times the black marks are on the side of the tomato, the black mark is a soft spot, and the flesh underneath is mushy. In the early spring, it was very dry so we watered. Now it has been raining so we are not watering as much.

A. Since you don't mention similar dark marks on leaves but on fruit only, sounds like a problem with stink bugs.

Stink bugs insert their snouts underneath tomato skin. The enzyme they leave at the sting point turns that area of the tomato into liquid. The bug then drinks the liquid. Sting points produce dark marks on the tomato. Discolored areas appear on tomatoes where fluid is removed. They’re often white, yellowish or light green. Damage can appear soft or knot-like.

To treat stink bugs
You can hand pick stink bugs and drown them in a bucket of water. You can also a heavy stream of water to loosen bugs off plants each day.

If you'd like to treat stink bugs more aggressively, you can apply insecticides like Sevin or Eight.

Learn more about stink bugs and how to prevent an infestation in your garden.

Good luck and happy gardening!
Your friends at Tomato Dirt