Uglynest Caterpillar Moth

2017 February 22

This smallish reddish-brown moth was at our porch light on August 1, 2016.


It’s pretty clearly one of the Tortricids, a large family of small-to-medium-sized moths that generally have that particular round-shouldered appearance when at rest.


It looks to me like the moth of the Ugly-Nest Caterpillar, Archips cerasivorana. They get the name from the tendency of the caterpillars to live in colonies that bind up clumps of leaves in an unsightly ball of silk, to protect the caterpillars while they eat the leaves. These nests look similar to the nests produced by several other species like fall webworms and tent caterpillars, but the uglynest caterpillars do not get nearly as large and are not hairy. They are smooth, pale-green caterpillars with black heads and a black shield on their shoulders, kind of like their relative the Oblique-Banded Leafroller.

Uglynest caterpillar eggs are laid in the fall, and overwinter to hatch just about the time the new leaf growth is starting. They are generally only moderately common and normally don’t significantly damage the trees that they feed on (mostly chokecherry, apple, hawthorn, roses, and relatives). However, every now and then there will be a significant outbreak that will completely blanket trees with their webbing. When this happens, the caterpillars will move on to other trees like birch and aspen once their preferred foodplant is gone. I expect that they are like the fall webworms and tent caterpillars in this respect, where the numbers crash soon afterwards due to massive increase in predator populations and the spread of diseases.

Comments are closed.