Forest Pest Insects in North America: a Photographic Guide

Greenstriped forest looper

Melanolophia imitata (Walker) (Lepidoptera: Geometridae)

Orientation to pest

Greenstriped forest looper, Melanolophia imitata (Walker), is a native geometrid found in moist conifer forests of western North America. Adults fly in spring and lay eggs singly (up to 80 per female) on tree branches and trunks. Larvae feed on foliage of all ages, but the previous year's foliage is preferred and damage is concentrated in tree crowns. In late summer larvae drop to the ground and pupate in the litter, where they overwinter. There is one generation per year. Larvae are solitary feeders and generally are not economically damaging. However, periodic outbreaks have occurred in Canada (especially British Columbia) that were destructive to western hemlock (Tsuga heterophylla [Raf.] Sarg.). Outbreaks in the past have ended abruptly due to natural causes.

Hosts commonly attacked

This moth feeds mainly on western hemlock (T. heterophylla), Douglas fir (Pseudotsuga menziesii [Mirbel] Franco), western redcedar (Thuja plicata Donn ex D.Don), true firs (Abies), and spruce (Picea).


This geometrid is found in western North America from Alaska to southern California and, in Canada, eastward to Alberta, in humid areas.

Images of greenstriped forest looper

Adult of greenstriped forest looper Marius Aurelian, 768x512 / 1536x1024
Larva of greenstriped forest looper Natural Resources Canada, Canadian Forest Service 550x356
Figure 1. Adult of greenstriped forest looper, Melanolophia imitate Figure 2. Larva of greenstriped forest looper

Important biological control agents related to this pest species

Past studies have shown that fungal pathogens such as species of Cordyceps and Entomophthora cause significant mortality to pupae in the soil.

Web links for information on greenstriped forest looper