Friday, June 19, 2015

Squash time

I love squash and last year I grew a couple plants in a flowerbed. They were beautiful plants--I think squash blooms are among the loveliest flowers. In the past when I’ve tried to grow squash, they were robust in the spring and produced an initial crop of squash. Then suddenly, the plants wilted, collapsed, and soon died. 
Photo courtesy Suzanne Allen
An examination would show a small hole or wound at the squash stem near the ground, a telltale sign of squash borer, a common and often fatal squash pest.

Photo courtesy Suzanne Allen
I had read somewhere that one way to prevent the adult moth from laying its eggs is to wrap the squash stem in aluminum foil. So shortly after planting my squash, I wrapped the stem. Then I waited while the plants really took off, making large beautiful leaves and quite a few blooms. When the first blooms did not produce fruit, I did not panic. I knew that squash are monoecious, which means that they have male and female blooms on the same plant . Often, the male blooms come out before any female blooms appear and, of course, male blooms can’t produce squash by themselves. But when the female blooms appeared but did not develop into fruit, it was apparent that something was wrong.

I had watched an episode of Family Plot where this problem was discussed and I suspected insufficient pollination. So I hand-pollinated them, which simply means taking an anther from a male bloom and transferring pollen to the stigma of a female bloom. This is a very easy task as long as you can distinguish between the male and female bloom, and my plants soon started fruiting. (This site shows the difference between the blooms and explains the hand-pollination process.)

Meanwhile, the squash moth was taking aim at my squash plants. I did not have a sufficient portion of the stem covered, so the moth simply laid its eggs further out on the stem. (I later learned that the recommendation is to cover the lower three feet of the stem--wouldn’t that be nearly the whole plant?) As luck would have it, the bed where the squash were growing had enough moisture that the stem rooted where it touched the ground. I cut off the original stem where the moth damage was, and the plant (at least part of it) survived.

Understanding the life cycle of the squash borer will help you defend against it. The adult squash moth emerges from the ground in late spring and lays its eggs on the squash stem. The eggs hatch in about a week and produce larvae, which feed their way into the interior of the stem, eventually causing the plant to die. The larvae feed for 4-6 weeks, then burrow into the ground to pupate. In some areas of the country, they will be done for the growing season and remain in the ground to await next summer when they will emerge to plague your squash again. However, in our area, there are two generations of adult moths. The eggs of the first generation remain in the ground 2-3 weeks, then they hatch and are back in August to lay eggs on your squash (if you have any by this time). This University of Tennessee publication explains the life cycle of the borer and gives suggestion for control.

My brother deals with this problem by planting a second crop of squash. This is a great solution in those areas of the country with a shorter growing season because there are no adult moths to lay eggs on the second crop. In our area, however, since there two generations of adult moths, the second crop is also in danger.

As for me . . . I decided that squash bought at the farmer’s market or grocery store is delicious, too!

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