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DISTRIBUTION AND PARASITIZATION OF COCOONS OF THE DOUGLAS-FIR TUSSOCK MOTH, HEMEROCAMPA PSEUDOTSUGATA (LEPIDOPTERA: LYMANTRIIDAE), IN AN ISOLATED INFESTATION1

Published online by Cambridge University Press:  31 May 2012

Donald L. Dahlsten
Affiliation:
Department of Entomology and Parasitology, University of California, Berkeley
E. Alan Cameron
Affiliation:
Department of Entomology and Parasitology, University of California, Berkeley
William A. Copper
Affiliation:
Department of Entomology and Parasitology, University of California, Berkeley

Abstract

Douglas-fir tussock moth cocoons were collected and their distribution recorded by crown level on white fir, Abies concolor, in northeastern California. Nine trees were sampled in two defoliation classes, light (20–30% defoliated) and moderate to heavy (50–80% defoliated). Cocoons were more abundant in the lower crown levels as defoliation became greater. The proportion of female cocoons increased toward the lower levels of the crown. An overall sex ratio of 1.2♂:1.0♀ was recorded. Significantly more male cocoons were parasitized than female. A list of the natural enemies of the tussock moth from the study area is given.

Type
Articles
Copyright
Copyright © Entomological Society of Canada 1970

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