02268naa a2200169 a 450000100080000000500110000800800410001910000190006024501770007926000090025652017060026565000220197165000100199365300130200370000210201677300610203712796902025-02-24       1987    bl uuuu     u00u1 u    #d1 aWICKMAN, B. E.  aPhenology of Douglas-fir tussack moth Oragiya pseudotsugata, egg eclosion and mortality in a thinned and unthinned stand (LepidopterabLymantriidae).h[electronic resource]  c1987  aHeat-unit accumulation and egg eclosion were monitored in unthinned and thinned white fir stands in southern Oregon. Degree-day accumulation and egg eclosion on the unthinned site were 7 to 10 days behind development in the thinned site. Parasitism and predation were higher on egg masses in the thinned stand. The ability to predict phenological development of insect-host systems has important applications for pest management as well as for research on population biology. Studies on phenology of the Douglas-fir tussock moth, Orgyia pseudotsugata (McDunnough), in California and Oregon (Wickman 1976a, 1976b, 1981) show egg eclosion is synchronous with host budburst. During population sampling for early instars, we observed a spread in developmental stages from 1st to 3rd instars on some sites. Phenological data suggest that egg eclosion on a given site is related to the amount of solar radiation reaching an egg mass; eclosion usually occurs first in the exposed tops of large trees and last in shaded areas under full forest canopy (Wickman 1976b). In the past, we compared tussock moth egg masses only from exposed trees but at different elevations (Wickman 1976a, 1976b, 1981). Egg eclosion was assumed to be early on exposed trees, and later in shaded habitats. In this study, our object was to compare tussock moth eclosion and egg mortality in two different environments at the same elevation—a thinned (exposed) and an adjacent unthinned (shaded) stand. The study was limited by available sites, egg masses, and instrumentation. These preliminary data are reported to encourage more definitive studies on the effects of silvicultural prescriptions on insect phenology and mortality.  aÁrvore Conífera  aPraga  aMariposa1 aTARGENSEN, T. R.  tPan-Pacific Entomologistgv. 63, n. 3, p. 218-223, 1987.