Subject: Caterpillars eating apple trees
Geographic location of the bug: Hershey Pennsylvania
Time: 03:14 PM EDT
Your letter to the bugman: I found these eating my apple tree leaves. What are they?
How you want your letter signed: Sue
We immediately recognized these as Prominent Moth Caterpillars in the genus Datana, but since we cannot currently access BugGuide for species identifications, we searched the genus name and apple tree and we found the Yellow Necked Caterpillar, Datana ministra, pictured on Discover Life where it states: “Yellow-necked Caterpillars clustered in a defensive group. When disturbed they flare up suddenly together, rearing their front and hind legs in a menacing ball to help ward off potential enemies. The larvae feed on shade trees in the genera Quercus (oaks), Betula (birches), Salix (willows), and Malus (apple trees and shrubs in the rose family, Rosaceae). Young ones skeletonise leaves; older ones eat whole leaves, except the stems. Once the larvae are fully grown at about 50mm, they drop to the ground and pupate in the soil, emerging as adults the following year. This species, Datana ministra, is in the moth family Notodontidae. Adults are difficult to identify from some other species in the same genus. The species ranges over much of the United States and Canada. While in some areas they are considered pests, they’re a joy to find, watch, and then poke gently with a twig. Boo!”