May 29 Army Worms Galore

Say hello to the eastern tent caterpillar (Malacasoma americanum) or at least a very close cousin. I have been working on the trails at Mt. Kearsarge State Park in central New Hampshire for the past few weeks and we have seen dozens of the thickly spun silk tents of this most social caterpillar. Hundreds of them hatch in early spring from one egg mass and soon begin constructing tents on sturdy branch unions nearby. The tents keep them humid and warm - they take advantage of spring sun by constructing the tents to face south. With such a dense population, the leaves on trees close to the tents may look like a wreck in a short amount of time. You can see evidence of that here as this voracious little eater mows down on half a leaf. Because their populations fluctuate, there will be an occasional year when it seems like these caterpillars are destroying their home ecosystems. However, they are a native species so don't worry about sustained invasions. An eastern tent caterpillar will pupate for 3 weeks and emerge from its cocoon as a moth with 2 white stripes running horizontally along its wings. They are brown and about an inch long.