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Archive for Wednesday, June 20, 2001

6-20 Gwyn

June 20, 2001

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Vine borers are little white caterpillars that worm their way into the stems of squash plants and eat the plant from the inside out. I can't say that I have ever seen one, but I certainly recognize their damage once it's done. One day you'll have a nice, bushy squash plant; the next day your plant will have collapsed in a heap and died.

Vine borers like winter squash best and in my experience seem to have a preference for spaghetti squash. Even so, they will go for summer squash, melons and pumpkins as well. When they kill a plant, the only thing to do is dig it out and dust the area with rotenone to kill any caterpillars and eggs that might be around, preventing another attack.

Vine borers turn into an orange and black moth with a wasp-shape body. It lays tiny red and orange eggs at the base of the squash plant's stems. Instead of trying to pick the adults out of the lineup buzzing around the garden, look for the eggs, which are the best clue that trouble is on the way.

When you find the eggs, smash them and sprinkle rotenone powder at the base of the plant. Rodale's "Encyclopedia of Organic Gardening" advises reapplying the rotenone every two days for a week.

While vine borers have been an occasional problem for me, squash bugs are an annual event. I envision a squash bug command central where a grid with blinking lights identifies gardens with squash in progress. With a wiggle of an antenna, the squash bug commander mobilizes the little army of soldiers that descends on my garden.

More likely, though, they overwinter in my garden and their yearly conquest requires a very short trip.

You have more time to wage war with squash bugs than with vine borers. Although some squash bugs are brown, the ones that appear in my garden every year are gray. They have a flat, oblong body that's less than an inch long, and lay reddish-brown eggs on the undersides of squash leaves.

When I'm checking my plants this time of year, I look for the eggs, which I immediately wipe off the leaves, making sure to smash them in the process.

If you find adult squash bugs, you can pick them off the plants by hand and kill them. If you find only a few bugs, you can bet that eggs are nearby.

Too often, however, the unwitting gardener finds dozens of squash bugs swarming the plant, and handpicking them presents too daunting a task. At that point, it's probably time to dust the plant and the soil around it generously with rotenone.

Rotenone is a naturally occurring insecticide, which makes it preferable to synthetic chemical poisons that don't break down as quickly. Rotenone will lose its effectiveness in a week in an outdoor garden, which means that after seven days it is generally safe to eat well-washed vegetables from a treated plant.

In my experience, rotenone is the most effective natural insecticide for battling bugs that chew. It's good for flea beetles on eggplant and bean beetles as well.

The problem with rotenone is that it is nonselective and kills other insects, such as the bees that pollinate your squash blossoms. As a result, if you use rotenone too early in the growing season, you may cut your plants' yield.

If you decide that you must dust, you can hand-pollinate the plants. Squash plants produce both male and female blossoms, and they are easily discernible. The males have straight long stems and a short blossom, while the females have a longer, almost hourglass-shaped blossom.

The easiest way to hand-pollinate is by touching the inside of the male blossom with a soft brush, such as the kind used for cosmetics, and then touching the inside of the female blossom.

Knowing the gender of your squash blossoms is important if you eat them, as many people do. Pick them before they open and pick only the male blossoms, because the females produce the squash. Be sure to leave at least one male blossom on the plant as a source of pollen.

-- When she's not writing about foods and gardening, Gwyn Mellinger is teaching journalism at Baker University. Her phone number is (785) 594-4554.

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