Hello UMD experts! I'm a visitor from Alaska. I spotted this this
on my run today, near Glen Burnie. I've never seen such a thing
of this size in Alaska. What do you think it is? Spiders? Tent
Any insight appreciated.
What you observed was a rather large and impressive nest of Eastern Tent Caterpillars. This early-season insect rarely does lethal harm to the trees they attack, since they typically go for wild cherries, crabapples, and other fruit trees that are capable of refoliating. The caterpillars will defoliate a branch or a small tree and then retreat to their nest. Eventually, they leave the nest and migrate individually to a secluded place where they go into pupation for a few weeks before emerging as adult moths and flying to a nearby target tree where they lay the next generation of eggs. The next generation hatches in the spring and establishes a communal nest.
They can be controlled by simply disrupting the nest and allowing birds to predate them, or spraying the nest and tree with a very safe product that kills only caterpillars.