Greenstriped forest looper
Damage, symptoms and biologyThe greenstriped forest looper is a common and occasionally destructive solitary defoliator. Severe defoliation may result in top-kill and occasional tree mortality.
Mature larva to 37 mm long. Head, unmarked green. Body, green with broad whitish green addorsal stripes and a narrow white subspiracular stripe. Spiracles marked by prominent yellow spots.
This species overwinters as a pupa buried in the duff. Adults emerge from mid-March (on the south coast) to mid-June (in the central interior) and deposit up to 80 eggs singly on branches and tree trunks. The larvae emerge soon after and initially feed on the underside of needles; later instars feed openly, preferring foliage of the previous year. Most feeding damage occurs in the crown of the tree. Larvae complete feeding by early August, drop to the ground, and burrow into the litter and pupate.
Life cycle (West of the Rockies)
Other informationIn British Columbia, outbreaks were recorded on the west coast of Vancouver Island in 1952 and 1963, on the Queen Charlotte Islands in 1963 and near Revelstoke in 1952.
Canadian Forest Service Publications
Diet and feeding behaviour
: Feeds on the leaves of plants.
- Free-living defoliator: Feeds on and moves about freely on foliage.
Information on host(s)
Amabilis fir, Engelmann spruce, grand fir, mountain hemlock, Rocky Mountain Douglas-fir, Sitka spruce, subalpine fir, western hemlock, western larch, western redcedar, western white pine, white spruce
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