Zucchini Houdini

by Cecil Bothwell


If you have a backyard garden, you've undoubtedly found by now that squash plants are too darn big. Zucchini and other summer squashes that are cute and manageable in June become Godzillas later in the summer, overshadowing everything within three feet. And the winter varieties make like Woody Guthrie and ramble "from California to the New York island." Cukes (which are also cucurbits - as are squashes, gourds, watermelon and cantaloupe) do the same, though their smaller leaves make them somewhat less overwhelming.


For most of us, the rational solution appears to be cultivating fewer plants (and thus keeping the Invasion of the Garden Snatchers down to a minor skirmish). Trouble is, late-season plant loss or wet-season pollination problems can cut productivity disastrously.


Fortunately, there are some simple tricks to help preserve your harvest. Squash borers - the bane of late summer - are particularly nasty for the vining varieties: acorn, buttercup, butternut, candy roaster, hubbard, pumpkin, sweet potato et al. The borer is the larva of the clearwinged moth, which lays its eggs on the lower stem. The dark-headed white grub crawls up the stem and drills a hole; entering the stem, it sucks the life out of the plant. The first sign is the sudden wilting of all the leaves farther out on the vine.


If you examine the main stem below the wilt, you will easily see discolored wounds oozing masses of a yellow-green, grainy substance known as "frass" - the German word for animal food that is widely used as a euphemism for caterpillar poop. Some gardeners stir up a dilution of the caterpillar killer bacillus thuringiensis (BT) and inject it into the stem with a hypodermic needle (some even use this method prophylactically, before infestation occurs).


I find it easier just to carry a small pocketknife. When I spot the entry hole, I slit the stem lengthwise above and below the wound. It's not hard to pop out the maggots (there may be more than one per hole), or you can simply run the blade straight through them. Cover the slit section with dirt and it will soon grow new roots. In fact, mounding dirt over healthy vines every few feet to encourage repeated rooting is another safeguard against borer loss. Invasion at any place on the vine will be less likely to sap moisture from the entire plant.


Once you've spotted an infestation, you should also check the stems bearing individual squashes. Unlike the leaves, the fruits don't immediately wilt, and by the time they exhibit damage, it will be too late. This is more urgent with the long-developing winter varieties than with summer squash (which are picked within days of pollination). And if aliens have invaded the squash, they may well be headed for the cukes, too, so check those vines as well.


Rotating crops is the best preventive measure, since the clearwinged moth overwinters underground. And if you have a serious infestation, you may have to resort to planting cucurbits only every other year so that the local infestation dies out for lack of food.


Squash plants are monoecious (meaning there are male and female flowers on the same plant) and self-fertilizing. The female blossoms can be easily identified by the small fruit (ovary) attached to the base and the clustered stigmata; the male flowers, set on slim stems, present a single, pollen-dusted anther. Especially in wet weather, the soft flowers sometimes collapse like wet blankets before beneficial insects have had a chance to transfer pollen from the male to the female blossoms. The simple solution is to break off the male flower, peel back the petal (save it for your salad), and insert the pollen-laden anther into and around the female stigmata. (This is also a good time for a birds-and-bees discussion with children of a certain age.)


By ensuring that every female blossom you treat gets pollinated, this technique can make a big difference in the yield of gardens containing few plants.


Of course, you will then face the wonderful problem of having too many zukes.





Publication date: 08/26/04