Yellow or green to almost black with a black stripe and numerous black spots on back. Up to 1 and 1/4 inches long.
Beet, peas, potato and spinach.
Eats leaves and buds of young plants. Rolls and folds leaves; ties them together with webs.
Throughout United States; especially troublesome in western states.
Destroy weeds in and surrounding garden, especially pigweed and lambsquarters, which may serve as alternate hosts for beet webworms. Clip off webbed leaves and destroy the caterpillars within them.
Pyrethrum spray or dust can be used but must be applied when caterpillars are young, before substantial webbing has been produced. The beet webworm's habit of enclosing itself in folded leaves protects it not only from insecticides but many natural enemies as well. Bacillus thuringiensis (2.0-3.0 tbsp in 1 gallon of water) can also be used.
Treat with a registered insecticide when insects appear in damaging numbers; repeat as needed.
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)