Tent caterpillars are baaaaack

[Red Squirrel]

Every so often these things just start to invade everywhere, this seems to be one of those years.

I just declared chemical warefare and started with lambda-cyhalothrin, but that stuff is quite potent and is harmful to good stuff like bees, so I really hate to use it in trees. (no flowers or anything in these trees so *should* be ok).

Wondering what else may work for these. I was thinking anything that can physically stop them from getting into the trees, but I think it's too late for that?

Any ideas of less potent stuff to use? I'll see how this stuff works out for me and go from there. I sprayed mostly the trunk and the main branches and then did a general spray of the leaves. This stuff basically is a residual and kills most bugs over time as they step on it. I think it's more meant for spiders and similar bugs though.

 

[stormkroe]

It seems they are quite allergic to WD-40 The tiniest spritz kills them instantly. I bet if you spray a ring around a test tree you'd see that they don't climb up (although they could still cross over through branches).

 

[turtile]

All you have to do is rip the tent down (when they are resting) to get most of them at once.

But if you care about other wildlife, keep them. The provide tons of food for birds and a few other things.

 

[FeuerFrei]

Propane torch, if you like crispy critters.

 

[Red Squirrel]

I still want the tree to survive though.

Looks like the stuff I sprayed is working but still early to tell. They arn't really "tenting" so there is no "nest" or specific area to attack, they're just everywhere in the tree and keep hanging off webs. I have this odd phobia of spider/similar type webs so it's really not fun to run into those strands.

 

[slag]

My dad used to douse the nest with WD 40 and then hit it with the propane torch. They would peel off the walnut trees and fall on the ground where he would hit them again until crunchy

Didn't hurt the tree.

 

[Linflas]

I still want the tree to survive though.

Looks like the stuff I sprayed is working but still early to tell. They arn't really "tenting" so there is no "nest" or specific area to attack, they're just everywhere in the tree and keep hanging off webs. I have this odd phobia of spider/similar type webs so it's really not fun to run into those strands.

When I was a kid there was a line of cherry trees along a street that we used to go catch those tent caterpillars from and somehow year after year both the trees and the caterpillars survived. I have had them in appear occasionally in a plum cherry tree next to my driveway and I just leave them alone. The tree doesn't really seem to suffer any lasting damage for the 3 weeks or so they are active.

 

[stormkroe]

They're wiping out hundreds of acres here, trees have zero leaves left. I hope they survive the attack.

 

[Paperdoc]

IMO, the best and safest stuff to use is called "BT", sort for "Bacillus thuringiensis". Some now call it BT-k to designate the kurstaki variant of it.

You buy this as a liquid containing these organisms in a suspension. You mix it as instructed with water and then spray. The water should NOT have any Chlorine residual in it (it harms the bacteria), so if your local tap water has high Chlorine levels, try getting rain water. I've used it with our local tap water which has only low Chlorine residuals (but not completely Chlorine-free) and it's fine that way.

BT is actually a soil-borne natural bacteria, and it is very specific for several varieties of test caterpillar and a few other such worms. It does NOT harm bees or most other insects, nor is it any hazard to people, dogs, pets, etc. You MUST spray it on the leaves of the trees infested with the caterpillars when they are actively eating. Don't spray too early before they hatch out - wait until it is obvious that the worms are eating lots. If it happens to rain shortly after that you may have to re-spray.

This material gives the caterpillars a totally fatal intestinal infection. In my experience, the day you spray you will see the worms eating actively, and possibly the next day. But by the day after that, they will all be moving slowly and not eating. Within a few days almost all of them will die and fall out of the trees.

I have used this over many years. Some years there are no tent caterpillars and no need to spray. But when they come I get this out and it always works. I find it stores well. What I don't use I leave in the bottle in my back shed where it can get warm in summer and freeze in winter, but it's still good after a few years.