I was surprised to see the number of trees with forest tent caterpillars (FTC) while walking the St. Olaf Natural Lands trail around the wetland just west of the Tostrud Center yesterday.
The DNR has a 2009 FTC update; the UMN extension has a FTC background page, written in 2000.
Is this a normal occurrence?
There are a bunch of them in the little “forest” the college has planted on the south hill below the new science center. Most of the ones I saw were on fruit trees, which are totally defoliated. It will be interesting to watch them to see if, as the article you linked to suggests, the little trees put out new leaves once the caterpillars have moved on. One year I had an infestation on a crabapple tree. I just cut off the branch where the cocoon was, fortunately, before the hungry worms could do their nasty work.
Jane, I noticed that many trees in the Lower Arb are infested, too… not defoliated like the ones you mentioned but with the silk-like pouches in the trees.
And if it gets really bad, beware:
http://www.dnr.state.mn.us/treecare/forest_health/ftc/impacts.html
I’ve had recurring problems with these in apple trees and generally do what Jane does: cut out the branch when the critters are at home (usually dawn or dusk). If you get them early in the cycle, the tree does fine. There is a crab apple tree in the median of Jefferson Parkway near Division that has has a huge nest in it.
.-= (Mary Schier is a blogger. See a recent post titled A $10 Greenhouse) =-.
I ran behind the new science center at st olaf, and about every 2 feet I saw those tent Caterpillars.
I had a tent in each of my apple tree’s this spring and had to creatively dispose of them. It was creepy! There are hundreds per tent.