How do we treat the soil after anthracnose on our tomatoes?

Asked September 10, 2015, 9:06 AM EDT

We believe our tomatoes suffered from anthracnose as they had a big blister-like, fluid-filled "bruise" on what looked like a beautiful tomato. When cut open, the inside was mushy. We pulled all the plants, but some root remains in the ground. We disposed of them far from our property. Now, how can we treat the soil this fall? Any ideas?

Douglas County Minnesota

1 Response

Crop rotation is the thing to do next year and considering spraying for anthracnose if 2016 is a year with lots of rain. Here are some Extension resources on tomato anthracnose:

Here is another article on What to Do about Tomato Anthracnose or Fruit Rot.

Prevention and control of anthracnose

Anthracnose can be prevented with fungicide sprays started as soon as there is fruit on the vine. Homeowners can use sprays with chlorothalonil (Daconil) or fungicide sprays with copper. Check the label to see if the product says it controls anthracnose and follow label instructions for use. If you have had problems with anthracnose in previous garden seasons a preventative spray program is a wise move.

Like other fungal diseases mulching and keeping plants off the ground by staking or tying them helps. Good airflow is important so don’t crowd plants. Some weeds harbor the disease so keep your garden weeded. Water at the base of the plant and try to keep plant foliage from getting wet. Tomatoes require well drained soil and wet soil often results in bigger problems with fungal disease.

If you get anthracnose in the garden it’s very important to remove all tomato plant debris and rotted fruits to a separate, remote compost pile or to plastic trash bags and the landfill. The fungus spores overwinter in tomato debris. And rotate your crops! This disease can also live in the soil through the winter and infect your plants next year.

Don’t allow your fruits to get over ripe on the vine. Pick them while red and still firm if you suspect you have anthracnose in the garden. Discard tomatoes with the rotted spots away from your garden, not in the compost pile either. If you pick tomatoes and notice small rotted spots cut out the spot and use them at once or toss them as they will quickly rot.

When storing tomatoes for fresh eating for a few days, try to put them in a single layer, not touching each other until used. If one has anthracnose that you didn’t spot it is less likely to spread to the other fruit if they don’t touch. And tomatoes should not be stored in the refrigerator! It ruins the flavor and they will actually spoil faster.