Anyway, the larvae should complete their feeding frenzy within a couple of weeks. The adults do not harm plants. Cankerworms Cankerworms, also knows as inchworms, have appeared across Kansas in the last week. Though the common names may suggest otherwise, larvae from both species appear in the spring. There is one generation per year.
Cankerworms feed on a wide variety of deciduous trees including oak, ash, elm, linden and apple.
Larvae vary from green to reddish-brown to black and have one or more white, pale green, or black stripes. Cankerworms are general defoliators and may skeletonize leaves. Eventually, only the midribs of leaves remain. Cankerworms can be detected by rapping on branches. This disturbs cankerworms, which betray their presence by dropping down on silken threads.