Insect Pests

Because the imported cabbageworm caterpillar is the same velvety green color as cabbage leaves, it can be hard to see. However, its chewing damage will be obvious. One caterpillar can eat several square inches of foliage a day. Also, if you see one, there are bound to be more. - Clemson University USDA Cooperative Extension Slide Series, www.insectimages.org

This white butterfly with a black spot on the wings is the adult imported cabbageworm; when you see it hovering around the garden, look out for its green caterpillars. - David Adams, University of Georgia, www.insectimages.org

The pupae of cabbageworms linger in and around the garden in winter to give rise to a whole generation of pests next year. - Whitney Cranshaw, Colorado State University, www.insectimages.org

The southern cabbageworm looks like the cross-striped cabbageworm, only it has long yellow stripes down its back. - Alton Sparks Jr., University of Georgia, www.insectimages.org

The cross-striped cabbageworm is recognizable by the stripes across its back; it walks like an inchworm. - Clemson University USDA Cooperative Extension Slide Series, www.insectimages.org

These caterpillars chew holes in the leaves of broccoli, cabbage, collards, kale, Brussels sprouts, mustard, and other related crops. When the cabbageworms first hatch, they are very tiny, but as they grow to 1 to 2 inches long, they quickly damage plants and deposit messy excrement on the leaves.

Affected leaves can be so badly chewed that they are practically worthless. Recovery depends on how bad the infestation is and whether there is much new growth, as in the case of mustard, kale, and collards.

Cabbageworms are easy to prevent with sprays of Bt (Bacillus thuringiensis). Use this to guard precious heads of cabbage and other cole crops. If already present, spray with pyrethrin or insecticidal soap for a quick kill and then guard against further infestation with sprays of Bt. You can also physically block the butterflies by using floating row covers in the spring to prevent the adult butterflies from laying eggs.