Biology and behavior of a larch bud moth, Zeiraphera sp., in Alaska.

Abstract

A possibly new species or subspecies of larch bud moth of the genus Zeiraphera, closely related to Z. improbana (Walker), was found associated with tamarack, Larix laricina (Du Roi) K. Koch, stands in interior Alaska. An outbreak occurred during 1975 and 1976 over an area of 240 000 ha (590,000 acres). Adult moths were mottled grayish in appearance. First instars emerged from the overwintering egg stage from mid to late May and began feeding as soon as the tamarack buds began to unfold. Pupation, adult emergence, and oviposition occurred from mid-June to mid-July and there was one generation per year. Defoliated tamarack stands turned reddish-brown color by mid-June as partially defoliated needles turned brown, but stands refoliated by mid-July. Parasites and disease killed 99.6 percent of the pupal stage in 1976.

Citation

Werner, Richard A. 1980. Biology and behavior of a larch bud moth, Zeiraphera sp., in Alaska. Res. Note PNW-RN-356. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station. 8 p