Houzz Logo Print

Help! Black ants are killing my tomato plants.

12 years ago

At first, I thought perhaps my yellow pear tomato plant had Fusarium or Verticillium wilt. One branch at a time was turning yellow and wilting.

But it was happening so fast! Each day, several branches would wilt and yellow. Then as I was inspecting the plant and pruning off dead branches, I saw a hole in the ground next to it. There were black ants, which looked like carpenter ants, streaming in and out of it. I sprinkled some Sevin dust around the hole, hoping that would take care of them. But the plant continued to die. Today, when it became obvious the plant would not pull through, I pulled it up to examine the roots. The tomato was a transplant, and I had planted it together with it's 1 quart peat pot in the ground. Despite the Sevin dust on the surface of the ground, There were healthy looking black ants swarming in and out of the peat pot!

The soil in the peat pot was a different texture from the surrounding soil, so this may be why the ants were attracted to it. The ants were also carrying some white matter which was in the potting soil. I am not certain if the ants were eating the roots to the plant, merely nesting in the pot, or eating the white specks of matter which was in the potting soil. Whatever their motivation, they killed my plant within only a few days.

Now the Sweet 100 plant next my yellow pear is showing the same symptoms. I sprinkled Sevin dust all around on the ground, more than before, but I think it would be more effective if I drown them with a liquid containing some safe organic pesticide that will not ruin the tomatoes.

Any ideas or suggestions? If what happened to my yellow pear is any forewarning, I do not think it will take long for my Sweet 100 plant to die.

Has anyone else had this to happen? Does anyone have any suggestions?

Comments (4)