We had the Tent, and Forest caterpillars here in CNY for the last 2 yrs. They hit us hard, stripped all the hard maples & oaks both yrs. The forest caterpillar is the one that does most the damage. They're not the ones that make the tents. I used SEVIN spray to kill the bastards all around my house. It works well. Far as protecting your tree's soon as show up, wrap plastic wrap around them a few feet up. Then take some vaseline, and wipe it onto the plastic wrap. They won't crawl up past the sticky vaseline.
They have been moving southward for the past 4-5 yrs. They started northern NY, possibly Canada, and have moved south. They're in Southern NY, and PA now. You will have to deal with them for 2 seasons. So do all you can to protect any tree's you consider valuable. They can kill tree's from consecutives yrs of defoliating them. The maples & oaks will releaf, but it takes alot of nutrients from the tree, making it suspectable to other environmental conditions, and diseases.
The two are easily identifiable. The tent variety has a solid strip down its back. These I wouldn't be too concerned about, they do minor tree damage. The Forest has white dots down its back. They can devour a full size tree in just a few days. You'll hear their droppings hitting the ground so much it sounds like rain! They also will web down from above like a spider. They are terrible, and I feel for all of you on dealing with it.

Matt/PA the pic you posted of a mature Tent Caterpillar is actually the mature Forest Caterpillar variety. The tent variety is similar to that, but with a solid white stripe.

Here's a link w/pics & info on them via NYSDEC websight.
www.dec.ny.gov/animals/7111.html

Cool.......learn something new everyday on here.

So they are both tent nesting types but one is just more destructive and a little different in appearance?

Edit: I see it now. I think I was thinking of the row of white dots just down from the solid stripe. The ones my dad has are definitely the tent variety and the pic I showed sure is the forest tent variety.
This link shows them side by side too:

http://www.tent-caterpillar.com/

Thanks guys, very informative. I had a nest of them in my weeping cherry tree. Killed them all with wasp spray.

my hunting spots in the pine barrens of new jersey were hit very bad last year. it looked like winter in august with the missing foliage. the poconos are loaded with them again this year. its funny how you dont hear anything about spraying for them.

http://www.wearecentralpa.com/content/fulltext/?cid=451



Gypsy Moth Concerns[/align]Reported by: Chris Cekot[/i][/align]
Saturday, Jun 9, 2007 @11:12pm[/i][/align]UNIVERSITY PARK, CENTRE COUNTY - Gypsy moths are out in force in parts of the Mid-Atlantic.Penn State scientists say they've never seen such a quick development of gypsy moth larvae before.Experts are predicting an especially bad year for trees, primarily oaks, which are the caterpillars' favorite snack.Forestry officials report nearly 700,000 acres of forests were defoliated last year because of the persistent bugs and this year could be worse.The critters are expected to cause damage in central and northeast Pennsylvania.

here are pics of the two that ive been seeing. my guess is the first one is a gypsy sorry about the pics they were off my cell

and this one a tent

what can be done to keep them off my trees, besides picking them off?

Here in south Jersey we have them bad ( galloway Township ). The township didn't spray this year, but I heard that next year they will spray again. We have some spots that don't have any leaves at all for miles. Now they are in the moth stage and laying eggs. The leaves are coming back for a second round.

I have been working for G.O.Hawbaker inc. for the past 3 mos ,,,driving east and west on I80 in the dump truck and from mile marker 161 west to the 130 is totally eaten up with those moths,,,both sides of 80 there is not a leafon an oak tree,,,now where i live off the mile marker 185 there seems to be no issues as of yet