Monday, August 17, 2009

Squash Bugs

Nothing is quite as ugly, smelly and destructive as squash bugs. Squash bugs, Anasa tristis, are a difficult garden pest to control, but there are options. Squash bugs prefer yellow crookneck summer squash, and they prefer this variety over zucchini and other squashes, although I don't find them very discriminating. They also favor pumpkins, and spaghetti squash. Squash bugs will thrive in, on, under, and around all squash plants, melons, pumpkins, cucumbers, and all cucurbits.

In my garden they seemed to favor the squash (crookneck and spaghetti), and avoided watermelon. Since my watermelons turned out quite good, I may plant more watermelon next year.

Sylvan Wittwer suggested to me, to use drip lines, and as the plants grow, move the lines further away from the plant base. Squash bugs like moist areas around the base of the plants, so removing the moisture from that area greatly reduces the attractiveness of the plant base. So this year, with a drip system installed, I tested this theory. My first row of garden, next to the lawn, had a Toquer Squash, a pumpkin, and a spaghetti squash. This was my control because it got overspray from the lawn sprinklers and the base of the plants were usually damp.

The remaining rows of cantaloupe, crenshaw melons, crookneck, zucchini, watermelon, and spaghetti squash, received the benefit of my moving the drip lines away from the base of the plants, as the plants grew. The drip lines ended up about 1 ft away from the base of the plants.

Clearly, the squash bugs preferred the first row of vines that tended to remain damp from the lawn overspray. Some of the other rows of melons, etc, where the base remained dry and open to the sun, squash bugs were much less prominent. So this does help--but the bugs will still come, they just won't be as "happy" and don't seem to reproduce nearly as fast in the dry conditions.

In addition to the above cultural practice, I also did the following:

1. Each day, I would scour the vine leaves for the eggs of the squash bugs, and squish these with my fingers. I was interested that the bugs laid eggs both under the leaves, and on top of the leaves. As the garden got bigger (quite a few melons), examining all the leaves became a bit of a chore, but I still tried to spend a few minutes each day looking for eggs, and eliminating them before they hatched.

2. I would also lift up the ends of the squash plants, every morning, and look for bugs, and squish them on the spot. This works well with the crookneck because you can lift up each vine all the way back to the base and see the bugs, and get rid of them. If you're squeamish, wear gloves.

3. Later in the summer, the squash bugs will accumulate under and on the fruit of the plants. As the foliage of the plants deteriorates through the summer, they will begin eating the squash, melons or pumpkins, etc. So I would lift or turn each squash (spaghetti), melon (cantaloupe and crenshaw) and expose the bugs, and squish them enmasse.

Historically, pesticides are not effective against adult squash bugs, and sprays or powders must be sprayed on the under side of plants and leaves to get to where the bugs are, and this is difficult to do. I do not even attempt to spray for squash bugs, and I tend to avoid using pesticides generally.

Strong, healthy, vigorous plants will withstand the effects of squash bugs better than weak or less thriving plants, so this should always be strived for. My experience is, doing nothing is not a good option--the bugs will win, your plants will lose, and you won't get much production.

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