Have you noticed an abundance of circular holes in sugar maple leaves this fall? It seems as if they are everywhere. If you are curious like me, you may have wondered what in the world created those holes and why are there so many this year?
Thankfully, when I noticed this phenomena, I was walking with some other naturalists that had seen this kind of thing before. They told me this was a sign of the Maple Leaf Cutter, a native moth.
I learned that the smaller holes are where a little caterpillar fed on the leaf in late summer and the two larger holes were cut and used as a kind of costume much later in the fall. The caterpillar attaches the two leaf peices together on either side of its body with silk, sandwiching itself in the leaves to protect itself from warblers and other predators that come through in fall looking for fat, juicy larva. Then, it overwinters in the leaves as a pupa to become a moth in the spring.
I wondered if this might hurt the trees, especially since Sullivan County produces the most gallons of maple syrup in NH. I was told that the Maple Leaf Cutter is a native insect and goes through population fluxes. It is at a high this year, but there seems to be something that keeps it in check. And since the leaves are gearing down for winter at the point they are cut, it doesn't seem to affect the trees much. So it doesn't seem like this moth is a pest, but more of a curiosity.
I for one, can't wait to look for the little leaf sandwiches moving down the bark of sugar maples next year.