I suppose to many it’s like a scene from a horror film – dozens of little green “worms” devouring the collard greens you’ve so carefully been cultivating. What’s a vegetable gardener to do besides kill and destroy?
First things first – know your enemy. There are several possible culprits, including cabbage loopers, diamondback moth larva, and the caterpillars of butterflies in the Pieridae family known commonly as Whites. The little guys shown to the right are the caterpillars of the Great Southern White (Ascia monuste) butterfly, which is native to the Southeast. Other native whites include the Checkered White (Pontia protodice) and the Florida White (Appias drusilla). These southeastern butterflies use native plants as hosts along with cabbage, including peppergrass (Lepidium virginicum), and only cause sporadic damage to food crops.
Perhaps the most notorious cruciform pests are the Small Cabbage White (Pieris rapae) and Large Cabbage White (Pieris brassicae) – once found only in Europe, but now common around the world wherever cabbage and other mustard crops are grown. Quite frankly, these butterflies and their caterpillars give our native species a bad name. They now outnumber our native fliers in many areas, and since they aren’t originally from here, the only plants they can host on are those on which they came – the cabbages and mustards that were brought here for food crops.
Being more of a butterfly lover than a vegetable gardener, I myself tend to grow collards and mustards only as hosts for Great Southern Whites, the most common visitor in my area. I can certainly understand the desire for others to control these caterpillars on their food crops though, so here are a few options:
- Plant “sacrificial” crops. In an area away from your vegetable bed, plant a few collards or mustards. As you find butterfly caterpillars on your food crops, remove them to the sacrificial plants where they can eat all they like without causing you problems.
- Use row coverings. The best way to keep butterflies from laying eggs on your plants is to place a barrier between the two.
- Watch for eggs and destroy them early. If yo don’t grow a huge amount of vegetables, it might be worth your time to do a daily search for eggs. (Click here for a picture.) You can remove them as you find them, or spray them with insecticidal oil.
- For more options, including biological and chemical control, take a look at this article by VegetableGardener.com.
It can be hard for nature-lovers and home gardeners to strike a balance between what’s good for wildlife and what’s good for your gardens. I’d love to hear about your own experiences with cabbage caterpillars, and how you manage them in your yard. Drop by the comments below and tell us all about it!