CONE AND SEED INSECTS IN DOUGLAS-FIR,PSEUDOTSUGA MENZIESII(MIRB.) FRANCO, SEED ORCHARDS IN THE WESTERN UNITED STATES: DISTRIBUTION AND RELATIVE IMPACT

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(Groté)). There appear to be great differences between orchards, but overallC. oregonensisandM. spermotrophuscollectively destroyed approximately 70% of the filled seed. Physiographic province significantly (PC. oregonensisandB. colfaxianaappeared to be related to land use or management factors, as well.