A Cape Cod Notebook 7/31/07

Educating Cabbage Worms

By Robert Finch

Every individual must come to terms with insects in his garden, but there's no creature in my backyard vegetable plot with which I have formed a more active and intimate relationship than the cabbage- worm butterfly. For years I'd watched the adult butterflies - small non-descript insects with sooty markings on their ash-white wings - dancing and twirling through the summer months over fields and gardens. I observed them with casual, ignorant pleasure, not even knowing their names. But when I came to garden myself, I learned that this graceful dalliance, if left unchecked, soon resulted in dozens of soft, fuzzy, inch-long, pale green caterpillars that quickly consumed all of my broccoli leaves.

There are sprays for cabbage-worms, of course, and I confess I've occasionally resorted to a bacterial insecticide. But more often I employ a control method I learned from a friend of mine: he educates them.

Educating cabbage-worms is a simple, but extremely effective method of training them to stay off broccoli plants. It consists of placing one's index finger directly above the catepillar to be instructed and one's thumb under the leaf directly beneath it, and then pinching firmly. As my friend assured me, "It always works. An educated cabbage worm never comes back."

Not only does it work, but I've found that it has made me a part of the butterflies' dance. Early in the morning I go out into the garden and train a dozen or so larvae off the broccoli leaves. Their bright mint-jelly guts squirt out one end, leaving their flattened skins to shrivel and blacken on the leaves.

When I?ve finished instructing them, I retire to the porch and watch the winged adults hopping and pirouetting over the partially chewed plants. They frequently fly in pairs, twirling and shifting about some common, invisible axis, like some airborne strand of DNA. At first I thought this might be some kind of lepidopteron mating flight, but one day at high noon, I ventured out into the garden and watched a pair of butterflies separate and land on different plants. Each had the extra pair of sooty wing spots that identify the female. Each gripped the edge of a leaf with her front pair of legs, curving her abdomen down and under to deposit her eggs on the bottom of the broccoli leaf, where they were virtually invisible.

Sometimes I'll try to quicken the tempo of our dance by scraping the new eggs off the leaves as soon as they're laid. But this is a tedious and lengthy task, and soon the heat of the midday sun drives me back onto the porch, where I sit in the shade, drinking lemonade, as once more the cabbage butterflies go dancing and twirling out over the garden, depositing more tiny eggs. Then, in late afternoon, I go out once again to administer another lesson to some of the newly-hatched cabbage worms.

So we move contrapuntally through the summer days - the butterflies, the worms, and I - locked in the ritualized steps of some formal dance: pinch, twirl, dip, scrape; pinch, twirl, scrape.

Broadcast July 31, 2007