Web worms, life cycle and management questions

Do web worm populations build up locally or do they fly in from somewhere else? I've got some pecans trees that have been almost totally stripped of leaves the last two years in the fall. If the population is local, I thought I'd try some dormant oil this weeend. Would dormant oil help? Maybe use Bt after they leaf out? i have Bt A.

Is all dormant oil organic?

Strange thing is when mine were stripped, a native pecan grove with massive trees, about six miles away, had no damage.  Maybe a natural pest is controlling them? Maybe the do fly in from somewhere else, and there just weren't enough moths to infest such huge trees?

Thanks!

I dont know the answer but i have a question.

I'm curious if your trees are arranged like an orchard. I spaced my pecans out fairly far, with other trees in between. I'm hoping this helps.

We had what seemed to be a bad web worm year in 2016, but my understanding is that they don't really do that much damage to trees.  They defoliate, sure, but the trees still produce, and it's quite unlikely that the worms will actually kill the trees.  So it seems like spraying, etc., is barking up the wrong... tree.

Are you talking about tent worms? If so, it is my understanding that some trees are healthy and established enough to survive the tent worms defoliation of their leaves. I would assume that means some trees won't be healthy enough to survive, though I haven't had any of my infected trees die.

Then again, I use a long pole with a small crook atttached to the end and stick it in the web, wrap all the tent & worms up I can reach like cotton candy and then dunk them in a big bucket of water. Dead worms get composted. I don't want to take the chance that my fruit or nut trees will not survive the tent worms.  Some webs are too high for my pole (with extension) to reach, but as long as my trees have leaves on the branches I can reach, the trees have survived. Some people suggest using fire instead of water, but there are often burn bans in effect here and fire can get out of control (whereas I've never had my bucket of water escape    ).

It helps to understand the life cycle of the pest. Here is info I found useful:
[url=https://prezi.com/g25hgxpl9_fi/forest-tent-caterpillars/
Helpful to scrape off the egg cases when you can see them in winter/early spring before the trees leaf out. Just search for "tent worm egg cases" to find lots of photos.

Thanks!  They're about 12 years old. They were completely stripped the year before last and almost completely last year. These are fall webworms, so the trees got some growth before things got bad. I don't think it will kill them. I wouldn't think nuts would be possible this year? Haven't had any yet. Some of them are in the front yard, and the trees looked awful.

The pole sounds like a great idea. I'll try that. I'm going to try the dormant oil. Someone had told me to encourage birds. I'm not sure what kind or how. I wouldn't mind putting up some bird houses or a feeder. I don't know much about birds.