Do you want to control webworms using the biological control method?
Do you want to control webworms using low-risk insecticides?
Do you want to control webworms using broad-spectrum insecticides?
Webworm abundance is sporadic because they are fed on by many parasites and predators. To preserve the effectiveness of these natural enemies, rely on pruning and selective insecticides if feasible when control action is warranted.
If webbing containing live caterpillars is abundant and cannot be pruned off or tolerated, apply Bacillus thuringiensis (Bt) or spinosad with a high-pressure sprayer to penetrate webbed foliage. The addition of a wetting agent to increase penetration of the silk by the insecticide enhances control. Bacillus thuringiensis kills only caterpillars that feed on sprayed foliage. A second application of Bt about 7 to 10 days after the first is recommended because of its short persistence. The somewhat-selective spinosad can adversely affect bees and certain natural enemies. Because spinosad is toxic to bees for several hours after the spray has dried, do not apply it to flowering plants.
A broad-spectrum, residual (persistent) insecticide such as carbaryl can be applied in the spring when larvae and the egg-laying adults are present. Do not apply carbaryl if bees are present; carbaryl is very toxic to bees and most natural enemies. Because it poisons parasites and predators, applying carbaryl may increase the frequency or likelihood of webworms becoming abundant again later or cause a secondary outbreak of spider mites.
The first line of defense, and one of the most effective for both spring and fall webworms is hand pruning the nests from trees. Regularly inspect host plants for silken webbing and prune out caterpillar-infested foliage if they are limited to small portions of the plant. If allowed to hatch, both the spring and fall webworms will quickly feed and head out to create a new cycle of worms.
https://thisismygarden.com/2019/08/how-to-control-webworms/
http://ipm.ucanr.edu/PMG/GARDEN/PLANTS/INVERT/webworm.html
Sreten null
Hi! I’m Sreten Filipović. I graduated from the Faculty of Agriculture at the University of Belgrade, with a master's degree in Environmental Protection in Agricultural Systems. I’ve worked as a researcher at Finland's Natural Resources Institute (LUKE) on a project aimed at adapting south-western Finland to drought episodes. I founded a consulting agency in the field of environment and agriculture to help farmers who want to implement the principles of sustainability on their farms. I’m also a founding member of the nonprofit organization Ecogenesis from Belgrade whose main goal is non-formal education on the environment and ecology. In my spare time, I like to write blog posts about sustainability, the environment, animal farming, horticulture, and plant protection. I’ve also published several science-fiction short stories.
You can find me on LinkedIn at https://www.linkedin.com/in/sreten-filipovi%C4%87-515aa5158/
