Environmental Entomology (1985) 14, 323-328

Torolf R. Torgersen and Richard R. Mason (1985)
Characteristics of egg parasitization of Douglas-fir tussock moth, Orgyia pseudotsugata (McD.) (Lepidoptera: Lymantriidae), by Telenomus californicus Ash. (Hymenoptera: Scelionidae)
Environmental Entomology 14 (3), 323-328
Abstract: Natural Douglas-fir tussock moth, Orgyia pseudotsugata (MeDunnough), egg masses, or laboratory-produced egg masses that were placed in the field, were used to determine the activity of egg parasites. Telenomus californicus Ashmead is the dominant egg parasite throughout the range of the tussock moth in the United States. Percentage of eggs parasitized varied substantially, from 0 to 65%, among 10 study areas in Oregon, California, Idaho, and Arizona. Aggregation of parasite attack as measured by Taylor's power law did not change over the range of parasitization rates observed. Parasitization appeared to be positively related to the outbreak potential of xeric outbreak-prone versus mesic nonoutbreak sites, parasitization being nearly 3-fold as high on the mesic sites as on the xeric sites. We developed a regression equation that relates proportion of egg masses attacked to total parasitization of eggs among masses. The regression provides a rapid, labor-saving way to estimate percentage of parasitized eggs.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
surveys/distribution/isolation

---

Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Orgyia pseudotsugata		U.S.A. (SW)
	Orgyia pseudotsugata		U.S.A. (NW)
Telenomus californicus (parasitoid)	Orgyia pseudotsugata		U.S.A. (SW)
Telenomus californicus (parasitoid)	Orgyia pseudotsugata		U.S.A. (NW)