Gypsy Moth In Weeping Larch - Confession and help, Please!

I am having my first attactk ever of gypsy moth. While I was concetrating on protecting my 60 ft+ oaks I neglected to look for other susceptible trees and got a nasty shock when I noticed a green needle drop on a mature weeping European larch. Close inspection revealed masses of caterpillars in the 1 to 2 in. range. When I say masses I mean masses! I have hand picked well over 200 throughout the day today. (This tree is about 5' X 5'.) A local nurseryman whom I trust recommended a quick knock down with a contact insecticide (Kelthane - off label use) followed by two sprays with Sevin a week apart. While reluctant to use any chemicals, especially the off label use, I was/am desparate to save the larch. It is a signature planting that hangs close to a 2000 gal koi pond. (I had to erect a hasty plastic tent to contain the Kelthane.) The Kelthane did a remarkable job of dispatching large numbers of the pest quickly, but I still handpicked the 200 later! Tonight I just got another dozen with a flashlight. Tomorrow I will handpick and tent again and spray with Sevin. I know many of you will be unhappy with the chemicals but really, what else could I do at this late stage? Is there anything else I should/could be doing now? What do I do next year?

I don't know much about them, but I hope we never get those nasty things down here.

IMHO, your best procedure would be to erect a Lymantria-proof barrier around your entire state to keep them there. . .

Hopefully the polyhedrous virus or some other natural control will catch up with your worms soon and begin to control their population. Until then, I think you probably are doing what needs to be done.

Guy S.

Why Thank You Guy! Actually If I could I would. I do NOT wish this scourge on anyone, anywhere ever!!! Two years ago the local extension agent distributed a soil fungus that is lethal to the caterpillar. They delivered, by request, and placed it in several locations on my property. I scrupiously followed the instructions on keeping the areas moist to allow for the fungus to survive. If there has been a benefit I am not seeing it. My understanding that in this area, as the moth marches through, the population builds astronomically for three or four years, then crashes, rises again in more modest numbers and becomes a resident pest that can be more easily controlled. I just hope we have something green left when it finally does crash. Unfortunately only one of my neighbors is protecting his oaks. In fact we have arranged Sevin spraying on the same schedule so that we both can cover our ponds from drift. The town where I live is also spraying the local parks. It is predominantely oak savannaha habitat. The state is so busy losing the battle against the emerald ash borer that they have turned their backs on small towns with limited budgets to help fund arial spraying of Bt. As a result the town is spraying Sevin from the ground. One Bt spray from the air would have been so much better.

I have become the queen of plastic sheeting and disposable gloves. Bird baths have to be covered as well as feeders. My oaks and my neighbor's oaks look pretty good at this point. Not too much damage. The number of egg cases will tell the tale this fall. The experts say that you can knock them off with those supersoaker squrit guns. Hope my aim is good.

This morning I could only find about 6 caterpillars on the larch and they looked pretty sick. Time now to erect the tent again for the Sevin spray. Polyhedrous virus? Is that something that you can encourage or what? What is the host?

I dunno the retails, but ask your extension office about it. I think the trade name is Gypchek. I believe it works similarly to Milky Spore in Japanese beetles, building up a population gradually as the host species increases. There is also an entomophagous fungus that might help. Perhaps one of those is what you already have applied.

Speaking of Japanese beetles, you could be really nice and take those back East too -- we have been trapping a gallon a day the past two summers, and I soooo eagerly await their appearance again this year. I used to feed them to the catfish in the pond, but they got sick of them. So now I use the durned beetles as a Nitrogen fertilizer supplement. Yeah, they do stink, but so do most other Nitrogen sources, right?

Guy S.

I read something one time about wrapping the tree trunk with duct tape and then putting Vaseline on it. Supposedly the caterpillars fall the the ground and then cannot climb back up.

Guy, the fungus you write of is the one that was supplied. I could not even sound out the spelling. I remember hearing something about gypcheck. That is definitely worth looking into. I quit growing roses about 5 yrs ago. Since then I have had no Japanese beetles whatsoever. It appears they they packed up and moved west. :-) Ahhh, nothing like the smell of pig manure for nitrogen. Now there is an odor, I'll tell you. How long does it take for the beetles to decompose?

escambiaguy - Some property owners with lots over an acre and dozens of oaks can't afford to spray. It can run around $2,000 per spray per acre. Many of them are using folded burlap bands with a sticky band. The caterpillers crawl between the flaps of burlap and get trapped. The home owner then goes out every day and removes the trapped insects. Very tedious and time consuming. I am told it is of moderate effectiveness but definitely better than nothing. Funny story about that. A small town in NW Ohio (can't remember where) tried that route in a public park. Seems some of the children who were curious and not well supervised got their hair caught in it. I envisioned small children screaming with their heads stuck to trees. I think the bands should have been a little higher!

Well, I finished hand picking all the critters I could find from the larch, tented and sprayed the Sevin. Within an hour they began dropping to the ground. This is unbelievable.

I vow never to let my guard down again. This fall I will inspect everything for egg masses and scrape or squirt off whatever I can reach. Next spring the battle is on.

Go git 'em, Snap!!! Stomp on them!

By the way, the dead beetles stop stinking after a couple of weeks, but the exoskeletons are still intact nearly a year later!

Guy S.