Various strategies for combatting fall webworms

Posted on December 14, 2023 by Vauxhall Advance

By Heather Cameron
Vauxhall Advance
Local Journalism Initiative Reporter

As fall fades into the background, so do fall webworms…at least for the season.

“Fall webworms are caterpillars of a moth species that are easily identifiable by the silk webs they construct on tree branches during the summer,” said Jorden Holst, Agricultural Fieldman for the M.D. of Taber. “These larvae feed on foliage, progressively enlarging their webs as they grow. They complete their life cycle, transforming into pupae during the winter months, and emerge as adult moths in the spring. The female moth lays eggs on the underside of leaves, covered in white hairs from her abdomen, initiating the next generation.”

Holst says that fall webworms thrive in various environments but are commonly found in trees, particularly in areas where there is an abundance of foliage for them to feed on and they often infest trees during the summer months, constructing their webs on crown branches.

“While fall webworms might not cause severe damage to trees individually, extensive infestations could weaken trees, making them more susceptible to further insect attacks or diseases,” said Holst. “Their unsightly webs and leaf consumption can also diminish the aesthetic appeal of trees, affecting the local landscape’s beauty.”

Dealing with fall webworms, Holst says, involves various strategies, including physical removal of webs (if feasible), pruning infested branches, and employing insecticides or biological control methods during their active feeding period. It’s essential, Holst says, to address these pests promptly to minimize their impact on trees.

In addition to fall webworms, Holst says, there are also various types of webworms apart from fall webworms including Eastern Tent Caterpillars, which create silk nests in the crotches of branches, and Webbing Caterpillars that also construct silken webs while feeding on leaves.

Holst says that the M.D. of Taber’s Ag Services team offers comprehensive support for managing fall webworm infestations in that they provide information, guidance, and assistance to concerned individuals about identifying, treating, and preventing infestations. Additionally, Holst says, they offer access to a tree sprayer for applying treatments effectively. Other resources on effective treatments, tree care, and pest management, Holst says, are also available through their services. 

Those who want more information on pest control, Holst says, are welcome to contact the M.D. of Taber’s Ag Services team at 403-223-8735 or visit the website at https://www.mdtaber.ab.ca/p/pest-control.

“It’s crucial to monitor trees regularly for signs of infestation and seek guidance from experts when dealing with fall webworms or any tree-related pest issues,” said Holst. “Prompt action and proper management can help preserve the health and beauty of local trees and landscapes.”