The microbial insecticide, Bacillus thuringensis (Bt), was applied from fixed-wing aircraft to approximately 700 acres of western spruce budworm host type at the rate of 12 billion international units (BIU's) per gallon of water per acre. The objective of this control project was foliage protection to insure future cone production...
An evaluation during the summer of 1985 showed that parasites were still exerting control on the larch casebearer on the Flathead NF. Parasitism ranged from 4 to 60 percent and averaged 25.2 percent in the 12 areas surveyed. Four species of parasites were involved. The most abundant was Agathis pumila...
In spruce budworm damaged areas, height growth loss can be a major factor in stand development. This survey was confined to top-killed trees. Estimates on height growth loss or nontop-killed trees was not attempted. Although spruce did not have as high a percentage of trees top-killed as the true firs,...
This evaluation showed that Bt provided measurable foliage protection 1 year after treatment, but no differences were evident after 2 years. We recommend future Bt tests include postspray population measurements in the pupal and/or adult, and/or egg stage, and that foliage protection be measured the following year. The effects of...
A multistage sampling survey to measure annual and cumulative mortality of lodgepole
pine by mountain pine beetle was conducted
on the Beaverhead and Gallatin National
Forests, 1978-79. The survey area, 270,000
acres, was stratified into three intensity classes
from aerial sketchmapping. This was followed
by large scale (1:6,000) aerial photography,...