Cones of Douglas-fir and ponderosa pine with extensive mold on external portions of scales were sampled for presence of fungi potentially pathogenic to conifer seedlings in nurseries. The major colonizers of cone scales and external seedcoats for both conifer species were Trichoderma spp. Penicillium spp. were also very common. The...
Douglas-fir beetle, Dendroctonus pseudotsugae Hopk., has caused extensive tree mortality in the North Fork Clearwater River drainage since 1971. In 1974, survey estimates indicated a continued decline in the infestation. Average group size decreased from a high of 158 trees per group in 1971 to 17 in 1974. Average area...
Root diseases were evaluated on the Reuben's Reserve, Nez Perce Indian Reservation, Idaho. Nineteen trees adjacent to two suspected root disease centers were pushed with a D-6 tractor to expose their root systems. Extent of root necrosis and decay was determined and related to level of crown thinning, chlorosis, and...
The unusually large amount of ice, snow,
and wind-damaged trees that occurred
during the winter of 1996-97 provided prime
habitat for populations of the Douglas-fir
beetle (DFB) (Dendroctonus pseudotsugae)
to build to epidemic numbers. Beetles
emerged during the spring and summer of
1998, attacking hundreds of thousands of
standing Douglas-fir...
An epidemic of Douglas-fir tussock moth was detected in northern Idaho
in 1972. In 1973, aerial surveys showed that nearly 100,000 acres contained
various degrees of visible defoliation. An egg mass survey of
five reporting units made in the fall of 1973 determined potential for
damage in 1974. Based on...
The Douglas-fir beetle, Dendroctonus pseudotsugae Hopk., has caused extensive tree mortality for the third consecutive year in the North Fork Clearwater River drainage in northern Idaho. In 1972, the infestation encompassed about 494,080 acres of commercial forest lands in this drainage. It was estimated from a tw-stage aerial photo-ground survey...
Douglas-fir tussock moth populations are monitored annually in northern Idaho and western Montana to insure early detection of changes from endemic to outbreak population levels. Adult moth trapping in 1982 was intensified and expanded into additional areas from 1981 because of concern that with each passing year the probability of...