Win the War on Webworms: Try these Methods

Mark Peterson

They’re everywhere. You know what I’m talking about – those ugly, nasty webworm nests insidiously attacking our pecan, mulberry and fruit trees. How can a homeowner stop this multi-legged menace?

First things first, know your opponent. Webworms are not worms at all, but rather caterpillars that turn into moths. The female lays eggs in early March on her preferred tree and shrub species. The caterpillars create a silken web to protect them from their enemies – birds and wasps.

Another important fact, webworms generally don’t search outside the web for food; they build the web around leaves and then eat them. Consequently, the web hinders natural control by predators and prevents effective treatments by humans. Note to self: Destroy the web and you eliminate the webworm.

Here are a few options:

  • Prune off the nest in early spring and on lower branches.
  • Break open the webs with a long stick to allow birds and wasps to eat the little buggers. Wasps can be quite voracious and eliminate a nest overnight.
  • Use insecticides containing Bacillus thuringiensis (Bt), spinosad, or carbaryl. Always read the labels carefully and use as directed.

Finally, I’ve received countless phone calls and e-mails over the years from desperate, agitated homeowners. For the record, webworms don’t pose a threat to tree survival. A nuisance, yes, but they themselves cannot kill a tree. Only repeated severe infestations adversely affect a tree’s health. So don’t lose any sleep over these creatures. I don’t.

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