Dipel (R) was applied by helicopter to three blocks of Douglas fir and Engelmann spruce infested with Choristoneura occidentalis Free., in southwestern Montana. Dosage was 1 pound (7.2 Bill) in 2 gallons of water/acre (453 g in 7.5 t/0.4 ha). A commercial surfactant, Bio-film (R) was added at the rate...
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...
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...
Mountain pine beetle infestations have increased in second-growth ponderosa pine stands in the Garnet Mountains since 1971. The extremely dry 1973 season resulted in an increase of Ips engraver beetle activity that was responsible for over half of the tree mortality in 1973. Commercial thinning is recommended to alleviate the...
Aerial surveys of the Nezperce National Forest in Idaho revealed 138,692 acres of aerially visible top kill and tree mortality due to repeated defoliation by western spruce budworm, Choristoneura occidentalis Freeman.
A small ground sample indicates that up to 47 percent of the grand fir volume was affected by top...
The pine butterfly, Neophasia menapia (Felder and Felder), currently is epidemic on approximately 40,000 acres of State, private, and National Forest land in the Bitter Root Valley. Butterfly populations were reported as becoming epidemic in 1969 and have continually increased to the present level (Bousfield and Dewey 1972).
Because this...
Over 10,000 acres of aerially visible western hemlock looper defoliation on grand fir was detected on State and Federal forests of central Idaho in 1972. This is the first report of this insect building up
in Region 1 since a widespread outbreak in 1937-39.
The western hemlock looper has the...