Cone and seed insects in douglas-fir, pseudotsuga menziesii (MIRB.) franco, seed orchards in the western united states: Distribution and relative impact

Document Type

Article

Publication Date

1-1-1985

Abstract

Douglas-fir cones were collected from 17 seed orchards in California, Oregon, and Washington in the fall of 1983. Cones were completely dissected and seed losses ascribed to the Douglas-fir cone gall midge (Contarinia oregonensis (Foote)), the Douglas-fir seed chalcid (Megastigmus spermotrophus (Wachtl)), the Douglas-fir cone moth (Barbara colfaxiana (Kearfott)), and the fir coneworm (Dioryctria abietivorella (Grote)). There appear to be great differences between orchards, but overall C. oregonensis and M. spermotrophus collectively destroyed approximately 70% of the filled seed. Physiographic province significantly (P<0.05) explained variation in damage by all insect species between seed orchards. In general, damage by all species increased from northern provinces to southern mountainous provinces. Damage by C. oregonensis and B. colfaxiana appeared to be related to land use or management factors, as well. © 1985, Entomological Society of Canada. All rights reserved.

Publication Source (Journal or Book title)

The Canadian Entomologist

First Page

1223

Last Page

1230

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