The Imported Cabbageworm: Coming to a garden near you!
If you’re seeing white butterflies flitting around in your garden, take a closer look at your “cole crops”. This is a large family of plants and includes broccoli, cabbage, turnips, kale, mustard, radishes, etc… They’re a favorite food of the cabbageworm. The butterfly lays individual eggs on the underside of the outer leaves. The larvae are tiny, green, velvety-looking caterpillars that are first seen when they’re only a tenth of an inch or so, but quickly grow to about an inch long. Sometimes even the spikey green chrysalis can be found on the plant. The larvae feed on the entire leaf, often from the underside where they’re better protected from sunlight and predators (which makes them harder to spot without turning over the leaves).
For most home gardeners, scouting for the caterpillars and removing them by hand is often the most effective method for control. There are chemicals that can be used to control them, however, they often need to either come into direct contact with the caterpillar, or be eaten by it. This can result in more damage in the meantime while the chemical takes effect.