Friday, March 27, 2009

More than You Wanted to Know about Squash

Every year, lots of people around here plant various kinds of squash in their gardens, and every year a lot of squash plants around here die an untimely death.

The usual cause is the squash vine borer, which, as an adult, is a moth that shows a striking bit of red-orange. These moths are pretty enough that I haven’t been able to convince my usual garden helper—my youngest son—to catch and squish them for me, so I have to do it myself (I have a little toy insect net that works just fine). Unlike many moths, these are active in the day, so a gardener can see when they start to be active in the garden. They lay eggs on the squash plants, and when the eggs hatch, the larvae that creep out bore into the squash stems where they start to eat away the inside of the plant.

Anyone who has watched a squash plant wilt a little more each day in the summer heat before finally collapsing into a limp heap of stem and leaf has, essentially, seen squash vine borers in action. Usually, a gardener in this area who doesn’t use pesticides gets a few zucchini off each zucchini plant in the summer before this collapse occurs.

Using pesticides will slow the borers down if the spraying begins early enough, but, besides the issue of having to deal with unfamiliar chemicals, which lots of people just don’t want to do, going the pesticide route means adding yet another chore to the gardening schedule. Those of us who are lazy, regardless of how we feel about pesticides, will look for another way around the problem.

One way is to just accept that the garden will provide a limited amount of squash. Another way is to look more closely at squashes in general, to see if nature has provided an alternative.

It turns out that there are four main species of squash that are grown for food: Cucurbita pepo, Cucurbita mixta, Cucurbita maxima, and Cucurbita moschata. Of these, the C. pepo group contains most of the squashes we like to grow and eat: zucchini, summer squash, acorn squash, spaghetti squash, and most pumpkins. Sadly, this group is highly susceptible to squash vine borers.

The C. mixta group contains mostly cushaw squashes, which are grown more as food for animals than for people, but this group is fairly resistant to the vine borers. I did read in the 2009 catalogue for Sand Hill Preservation Center that cushaw squash are good to eat when prepared correctly. Cooking instructions appear in the catalogue.

The C. maxima group includes banana squash, the Cinderalla pumpkin (Rouge V’if D’Etampes), buttercup squash, and hubbard squash. I’ve read conflicting information about the resistance of these squashes to vine borers, but I did try to grow buttercup squash one year, and it did not survive long enough to produce a mature fruit. On the other hand, I have a friend who grows the Cinderella pumpkin just about five miles away, and she has had no trouble with borers on them. It may be that this group is variably resistant to the borers, depending on the variety. Or, it may be that my yard is just fatal to some squashes.

The C. moschata group is most resistant to the borers. The most familiar representative of this group is the butternut squash, but this group also contains the cheese squashes, Seminole Pumpkin squash, and a variety of squash sometimes called Trombocino Rampicante (sometimes also called Zucchetta) that, when immature, is fairly similar to zucchini.

The substitution of Trombocino squash in the garden for zucchini makes having “zucchini” all summer long possible, without having to work out a pesticide schedule for the borers. One drawback to this variety is that it vines vigorously. In small gardens, some plan for how to handle the vines needs to be worked out, or they will sprawl all over the lawn. Also, it isn’t a perfect substitute; the taste is similar, but I think it is closer to zucchini-flavor when peeled. Also, it is firmer, and needs longer cooking. This can be an advantage, since sometimes zucchini falls apart when (accidentally!) left cooking too long. If immature fruits are left on the plant to mature, they become a bit like butternut squash, but less sweet.

Examination of specialty seed catalogues (like that for Sand Hill Preservation Center) shows that more C. moschata squashes exist. These squashes, which are mostly what we would call winter squashes, will in general be resistant to the vine borers, so anyone who really loves squash and has been getting frustrated over all the dead squash plants might benefit from sticking with this group. Anyone still up for a bit of experimentation might try the C. maxima or C. mixta group.

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