The fall webworm has already been spotted in South Louisiana and in St. John the Baptist Parish.

Fall webworms are caterpillars that create irregular shaped silk webs in a variety of trees. The silk webs will continue to increase in size as the caterpillars feed on the tree’s foliage. Webworms only fed on the leaves inside the web and do not typically leave the protection of the web. Common hosts include oak, boxelder and pecan trees, other hardwoods and some evergreens. Up to four generations of webworms can occur each year.

Though unsightly, infestations of webworms will not kill your tree. Healthy trees will recover naturally from webworm damage with no long-term effects.  

Webworms can be controlled by simply cutting and removing the end of the branch that contains the web. Periodic inspection of trees should be done so that webs can be removed before they get too large. Chemical controls are also available, insecticides containing active ingredients such as B. t. (Bacillus thuringiensis), Spinosad and Carbaryl work well. When applying an insecticide be sure to penetrate the web so that the chemical can make contact with the pest. Always completely read the product label when using any type of insecticide treatment.

For more information contact the St. John Parish LSU AgCenter Extension Office at 985-497-3261 or visit www.lsuagcenter.com.

Mariah Brock is the LSU AgCenter county agent for St. John Parish, she can be reached by email at mbrock@agcenter.lsu.edu.