The top image shows imported cabbageworm larvae and leaf damage. The lower left image is an adult cabbageworm butterfly. The lower right image shows cabbageworm larva on underside of kale leaf.

First of twoAs gardeners, we enjoy the feeling of accomplishment we get from growing and eating our own vegetables. It’s so satisfying to stroll through the garden, checking on the progress of our future dinner.Then — we find bug critters helping themselves to the plants we have worked so hard to grow.This article is the first of two on managing garden pests we most love to hate.One of the most destructive pests is the cabbage worm.If you grow cabbage, broccoli, cauliflower or any other cruciferous vegetable, you may be familiar with small white butterflies with black markings flitting around your garden.These are the adults of the imported cabbage worm scouting for host plants where they will lay their eggs. Cabbage worms came from Europe and have been seen in North America since 1860.Their larvae are the velvety green caterpillars you find eating holes in the leaves of your vegetables and floating to the surface of your blanching water when preparing your harvest to eat or preserve.Because these larvae take only four to five weeks to mature and transform into adults, there are typically three generations each growing season. That’s a lot of pests to manage!Here are some ways to prevent and control these insects.Remove plant litter after the growing season, because cabbage worms overwinter as a pupa or chrysalis in plant debris and emerge as butterflies in the spring.Use floating row covers or cheesecloth to prevent the adult butterflies from laying eggs; make sure the edges are anchored well to the ground.Grow cabbage as an early crop so it reaches maturity before cabbage worm populations have built up in late summer.Consider planting turnips, kohlrabi, rutabaga, kale or red cabbage, which are less appealing to cabbage worms.Plant flowers and blooming herbs around your garden to provide a nectar source for beneficial predator insects such as ambush bugs, shield bugs and vespid wasps.Regularly inspect your crops for the white butterflies, irregular feeding holes in the leaves, and dark green fecal pellets scattered on or beneath the plant.Handpick the caterpillars and drop them into a bucket of soapy water.If the above steps are not sufficient to manage your infestation, there are insecticides that are safe to use on food crops.One of these, Bacillus thuringiensis (Bt), is an organic bacterial insecticide that is highly effective, but only on the young caterpillars. Direct sunlight deactivates Bt quickly, so apply late in the day or when it is cloudy.Spinosad, neem and pyrethrin are botanical insecticides that can be safely sprayed on the plant. Be sure to treat the underside of leaves where the larvae feed, which is easier when using a dust rather than a liquid.Avoid broad spectrum insecticides like carbaryl (Sevin) that can harm beneficial insects and birds. No matter what your choice, follow labeled recommendations for rates and timing of applications.If you have additional questions regarding cabbage worm control or other gardening topics, please contact the Master Gardener Greenline at 724-287-4761, Ext. 229.

Mary Reefer has been a Master Gardener since 2012. She lives on a farm with her husband in Mount Chestnut. She enjoys both vegetable and flower gardens. She is a Greenline volunteer answering a variety of horticultural questions. In her spare time she is studying to be a certified botanical illustrator at Phipps Conservatory.