caterpillar alert: who’s eating my cabbage and broccoli?

THINGS WERE GOING SO WELL. Even the most-vulnerable crops—the crucifers, or Brassicas, including cabbage, Brussels sprouts, broccoli, kale, collards—were looking beautiful. Big, strong plants grown under row covers for about six weeks (successfully defeating flea beetles, at least) are suddenly under attack by small, velvety green caterpillars. What’s up, and what can I do about cabbage “worms”?

Though I cannot see without a hand magnifying lens if they have the requisite tiny markings, I’m betting from its overall appearance and velvety surface that this is the larval stage of the cabbage white butterfly, Pieris rapae, because I have also seen its adult stage flying around, a smallish butterfly with a couple of smudgy spots on each white wing.

This article from Missouri Botanical Garden is extremely detailed on my latest visitor, also known as the imported cabbage worm, and other pests of cabbage relatives, including cabbage looper and the caterpillar of the diamondback moth. The latter two caterpillars are smooth, not velvety, among other clues to differentiating among the three.

As with all caterpillars, these can be controlled with the non-chemical biological control called b.t. (Bacillus thuringiensis), often sold as Dipel or Thuricide, but I don’t use it (tempted!). Nor do I use pyrethroids, which are also effective, apparently, but synthetic and not approved for organic production, or even natural pyrethrum/pyrethrin, which is permitted for organic use.

Instead, with my home-garden sized small number of plants, I’m making the rounds early and again late each morning, and hand-picking the sticky little beasts and—yes—squishing them. The challenging part is how well-camouflaged they are, often resting on leaf midribs as

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