For the last two years, I have had problems with my cucumber and squash plants. Both years, the plants started out well. Both years, the initial crop of cucumbers was abundant, but the summer squash crop was minimal. The cucumbers wilted and died by early August. The summer squash matured only 2 fruit on two plants this year. Giving up on the squash plants, I removed them.

The leaves had spots of whitish growth on them and it seems that squash that set would eventually shrivel up, or in the case of the winter squash, was covered with a grey fuzzy fungus. It did not seem like the leaves were being eaten by insects though I did see some squash bugs (I think) when I removed the plants.

I replanted summer squash in a different area of the backyard and see the same whitish spots on the leaves (top and bottom) and stems occuring. The leaves are intact for the most part. This plants is not setting fruit yet.

What is your best guess as to what is happening here? What is the best means of controling it on my plants or with the soil in this area?

Thanks

Dear Laura:

You are experiencing 2 or more different things going on with your cucs and squash.

The whiteish spots on the foliage is/was likely powdery mildew. This is a disease that was pretty common this summer with the kind of rainfall and humidity we have had. You can spray to prevent this or better is to grow powdery mildew resistant varieties. The young fruits that develop on infected plants can easily fail to develop and they are very sensitive to several fruit rots. The cucumbers may have been infected by a wilt disease, spread by cucumber beetles feeding early in the Spring. To prevent the disease, you need to prevent the cucumber beetles from feeding on the vine crop for as long as possible. You can use insecticides containing carbaryl and make treatments as soon as you see the ground opening up where the seed is emerging and weekly for several weeks. You can also place a barrier between the plant and the beetles using the fabrics designed for this purpose. They are very light in weight, allow lots of sunlight through, yet prevent the beetles from feeding. The fabric will need to be removed when the plants get to big and for sure as they start to bloom so insects can pollenate the female flowers.

Hopefully this information is helpful. Good Luck next season!

Sincerely, Richard Hentschel