Epidemic levels of the pine butterfly, Neophasia menapia (Felder and
Felder) have been evident in ponderosa pine stands in the Bitter Root
Valley since 1969. Evaluations of this infestation were initiated in
1970 to assess overwintering egg populations at 20 locations within
the infestation (Ciesla et al. 1971). Defoliation was...
A study was made to determine the distribution of parasites of the larch casebearer, Coleophora laricelia, within crowns of western larch, Larix occidentalis. The most common parasites recovered in order of their abundance, were: Agathis pumila (Ratz.), Diciadocerus sp. near westwoodii, Spilochalcis albifrons (Walsh), and MesopoZobus sp. Parasitism by A....
Dwarf mistletoe is known to reduce both height and diameter growth and thus reduce the yield of an infested stand. This comparison of two similar stands--one healthy and the other infested--gives an indication of the impact of this parasite. The healthy stand has produced 1.5 times the board foot volume...
This report documents the establishment of a study to determine the effect of thinning on incidence of mountain pine beetle, Dendroctonus ponderosae Hopk., infestation in second-growth ponderosa pine stands in western Montana.
Although insufficient time has passed for a similar study in Oregon to yield a solid base for a...
An evaluation of the status of bark beetle infestations in ponderosa pine stands on Blue Mountain, Missoula District, Lolo National Forest, was made March 30 and April 4, 1972, at the request of personnel of the Missoula District.
Extensive group killing of ponderosa pine in the vicinity of Blue Mountain...
The mountain pine beetle, Dendroctonus ponderosas Hopk., showed a significant advance northward from the 1970 infestation boundary, encompassing almost one-third of the total Park acreage. A fall survey conducted in the Park showed an average of 71.1 trees per acre with red or fading foliage from previous year's attacks and...
A 3-year evaluation of Douglas-fir cones in Montana and Yellowstone National Park, Wyoming, showed the western spruce budworm, Choristoneura occidentalis Freeman, and midges were the most common and injurious insects found each year. Injury was so severe at some plots that no sound seeds could be found.