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...
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...
A mountain pine beetle infestation developed in lodgepole pine stands in the Gold Creek drainage in 1974. From 1974 to 1976 approximately 19,000 trees with an estimated volume of 10,210 cu m were killed. Based on buildup ratios, stand structure, size of trees, and residual green stand, it is predicted...
Mountain pine beetle populations developed to epidemic level in lodgepole pine stands in 1973. Approximately 426,355 trees were killed on 3,433 hectares in 1976. Infestations are expected to intensify in areas of current infestation and develop in uninfested stands. It is predicted that 1,722,288 trees will be killed in 1977....
An infestation of a defoliating weevil, Magdalis gentilis LeConte, was
reported in July by Hank Manning, Judith Ranger District forester, Lewis
and Clark National Forest. The infestation occurs in precommercially
thinned stands of lodgepole pine, Pinus contorta var./atifblia Engelm.
in the Moose Creek drainage. Although damages caused by M. gentilis...
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...
Mountain pine beetle infestations developed to epidemic level in lodgepole pine stands on the Yaak District in 1972. Approximately 56,282 trees were killed from 1973 to 1975. By 1975, 2,068 ha were infested. This increased to 7,138 ha in 1976, representing a threefold increase. Current infestation occurs on 13 percent...
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 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 infestations in the Snell Creek and Warland Peak areas were evaluated in October 1975. Based on current buildup ratios, tree diameter distributions, stand composition and phloem thicknesses, there appears to be limited opportunity for epidemic potential in either area. Management alternatives are discussed. Selective logging is recommended...