Cabbage, Broccoli: Green Worms (6253)

Those plain white butterflies that are so common in the summer are the adult stage of the imported cabbage worm. Females lay yellow, bullet-shaped eggs on many plants in the mustard family, including brussels sprouts, broccoli, cabbage, swiss chard, kale, and turnips. Velvety smooth, green caterpillars hatch out within a week and eat huge holes in the leaves and fruits of susceptible plants.

This European insect is one of the most common garden pests. Cabbage worms spend the winter in a pale green or tan chrysalis. The first adults appear in mid-April, and there are at least three generations each summer. Populations build in late summer and make it impossible to grow susceptible plants in the garden without some worm feeding.

You have many control options to stop imported cabbage worm caterpillar attack. Planting cole crops early in spring allows plants to mature before insect populations build to damaging levels.

You can physically protect summer and fall crop plantings with floating row covers such as Reemay or similar products. This prevents the butterflies from laying eggs on the plants.

Handpicking caterpillars works, but takes a lot of time.

Bacillus Thuringiensis, a natural bacterium, gives good control against cabbage worms. Look for it in garden centers as Dipel or Thuricide. It works best on small caterpillars, and should be applied in late afternoon.

Caterpillars stop feeding within two to three hours and die within two to three days. This bacteria does not harm beneficial insects, animals, or humans. You must apply it every fourteen days, and there are no harvest restrictions. Most garden insecticides also control imported cabbage worm if you apply them every two weeks during the growing season. Do not start treatments until you see signs of chewing damage. Spray plants thoroughly to successfully control the worms. Rain may wash off the chemical; if this happens, reapply. Follow all label directions as far as dose, harvest restrictions, and acceptable crops.

For more information on this subject, Please visit the College of Agricultural Sciences Publications Web site.

Feel free to forward, post or reprint any of the "Solutions" in their entirely, but please credit http://www.solutions.psu.edu/ as the original source of information, and please do not change the content.