Forest Pest Insects in North America: a Photographic Guide

Spearmarked black moth

Rheumaptera hastata (L.) (Lepidoptera: Geometridae)

Orientation to pest

Spearmarked black moth, Rheumaptera hastata (L.), is a native North American looper found from North Dakota to British Columbia and Alaska. It feeds mainly on birch (Betula). Adults fly in spring. In Alaska, eggs are laid singly or in clusters on tops of leaves, from mid-June to early July. Young larvae feed gregariously between two leaves webbed together to make a sandwich-type shelter. Larvae feed on both new and old-growth foliage and usually feed just on the upper side, skeletonizing leaves. Larvae mature in July and August, drop to the ground on silken threads and pupate in the leaf litter, where they overwinter. There is one generation per year. This moth is a serious defoliator of paper birch (Betula papyrifera Marsh.) in interior Alaska. Epidemic populations have occurred at 15- to 17-year intervals, persisted for 2 years, and then collapsed from natural causes.

Hosts commonly attacked

This species feeds mainly on mainly on birch (Betula spp.). In Alaska, paper birch (Betula papyrifera Marsh.) is the preferred host, but larvae also feed on species of alder (Alnus), willow (Salix), and rose (Rosa). In Canada, the insect also feeds on sweetgale (Myrica).

Distribution

This geometrid is found throughout Canada and Alaska, and the northern United States, with southerly range extensions along mountain chains (Cascades, Rockies, Appalachians).

North American distribution of spearmarked black moth USDA Forest Service • Forest Insect & Disease Leaflet 156
Figure 1. North American distribution of spearmarked black moth, Rheumaptera hastata

Images of spearmarked black moth

Larva of spearmarked black moth Graham Finch - Contact for Permission at m.finch4@ntlworld.com 768x512
Figure 1. Adult of spearmarked black moth, Rheumaptera hastata Figure 2. Life stages (adult, eggs, larva, pupae) of spearmarked black moth Figure 3. Larva of spearmarked black moth
Tent made by larva of spearmarked black moth, where it feeds Graham Finch - Contact for Permission at m.finch4@ntlworld.com 768x512
Birch defoliated by spearmarked black moth Peter A. Rush, USDA Forest Service, Bugwood.org 768x512
Figure 4. Tent made by larva of spearmarked black moth, where it feeds Figure 5. Birch defoliated by spearmarked black moth

Important biological control agents related to this pest species

Parasitoids that have been reared from the overwintering pupae of this moth include Aoplus ruficeps vagans Provancher (Ichneumonidae), Coccygomimus aquilonius (Ichneumonidae), and Cratichneumon sp. (Ichneumonidae). The parasitoid Meteorus niveitarsis Cresson (Braconidae) has been reared from larvae.

Web links for information on spearmarked black moth

Articles

University of Massachusetts, PSIS/Entomology USDA Forest ServiceUniversity of Georgia Center for Invasive Species and Ecosystem HealthUniversity of Georgia