summer squash

Asked July 26, 2020, 12:35 PM EDT

Hello-My Zucchini plants have started to rot at the base of their stalk. In some ways it looks like bacterial wilt to me, but I have never seen bugs of any sort on the plants, until they start to rot and then they are covered in ants. The fruit on the vine is starting to rot too. Thank you! Cora

Baltimore Maryland

1 Response

Squash stem injury is most likely due to the squash vine borer. The ants are there for the leftovers.
Please see our web page on the squash vine borer:
https://extension.umd.edu/hgic/topics/squash-vine-borer-vegetables
There are two generations per year. Planting in mid-June may allow you to avoid infestation by the first generation. The mated females are active laying eggs in late May-early June in Central MD.

Using transplants shortens the time that the plant is in the ground leading up to fruit production. This can help reduce risk to pest insects in general.

Some gardeners and organic farmers find that planting summer squash several times, protecting plants with floating row cover material, and removing borers from infested plants are three dependable techniques for ensuring a good harvest.

The rot on the fruit looks like Choanephora rot disease. This is common during warm, humid, wet weather. The pathogen attacks the flowers and then moves into the fruits. Simply remove flowers once the fruits start to grow (after pollination and fertilization of ovules). Remove affected fruits. Pruning out excessive inside foliage can help with the problem.
https://extension.umd.edu/hgic/topics/choanephora-rot

Marian