Dull grayish yellow, fat, 5 brownish purple stripes down back. Up to 1/2 inch long.
Cabbage, cauliflower, kohlrabi, turnip, mustard and kale.
Bores into buds and stems killing young plants. Feeds under a protective web that it produces. Does little or no damage to spring crop.
Southern United States.
Cabbage webworm moths lay eggs on the buds of brassica plants. In about three days larvae hatch and feed on the tender buds. Later the larvae migrate along the leaf veins, feeding and spinning silken webs. In about two weeks larvae reach maturity and pupate in plant debris on the ground. Moths emerge from their cocoons in approximately one week. Multiple generations occur annually in Virginia.
Clip-off webbed leaves and destroy the caterpillars within them.
Bacillus thuringiensis , or Bt, (Bactur, Dipel, SOK BT, Thuricide) 2.0 to 3.0 tbsp in 1 gallon water. Bacillus thuringiensis will work but its results are not quickly observable; caterpillars get sick the first day and die later. It is not necessary to wait before harvesting after an application of Bt. Pyrethrum spray or dust can be used but must be applied when caterpillars are young, before substantial webbing has been produced.
Apply a registered insecticide as soon as plants appear. Direct insecticide to the undersides of leaves.
Notice: Because pesticide labels can change rapidly, you should read the label directions carefully before buying and using any pesticides. Regardless of the information provided here, you should always follow the latest product label when using any pesticide. If you have any doubt, please contact your local Extension agent or pesticide dealer for the latest information on pesticide label changes.
Disclaimer: Commercial products named on this site are for informational purposes only. Virginia Cooperative Extension does not endorse these products and does not intend discrimination against other products which also may be suitable.
Prepared by Alexandra Spring and Eric Day (Modified from a publication by the USDA)