Mortality from various causes was recorded in a Douglas-fir tussock moth, Orgyia pseudotsugata McD., outbreak southeast of Coeur d'Alene, Idaho, in 1974. Observations began June 27 when about 50 percent of the larvae were second instars and continued until pupation. Within a 35-day period, there was a 93 percent average...
Emerged beetles were first collected July 17 and peak emergence occurred between August 10 and 26, 1975. Density of attacks averaged four per 0.5 ft. 2 (0.05 m2). Parent to brood ratio was 1:4.6. Thirteen associate insects, representing six families of Coleoptera and one of Diptera, were recovered. Associates included...
Mountain pine beetle reached epidemic levels in the Lap, Cool, Lang, and Caribou Creek drainages in 1974. From 1973 to 1975, approximately 56,282 trees with an estimated volume of 4,365,660 board feet were killed in these areas. An additional 61,721 trees are predicted to be killed in 1976. Currently infested...
Mountain pine beetle has occurred at epidemic level in lodgepole pine stands in the west Gallatin River drainage since 1969. Infestation now encompasses about 5,500 acres. Since 1969, approximately 463,212 trees, with an estimated volume of 20,529,244 board feet have been killed. Approximately 69 percent of the stands on the...