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.
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...
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...
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...
Mountain pine beetle, Dendroctonus ponderosas Hopk., reached near epidemic levels in lodgepole pine stands in the Sulphur Creek-Black Butte area. Lodgepole pine are probably more susceptible due to the overstocked conditions of stands, and high incidence of girdling of the base of trees by porcupines. The infestation in this area...
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...
Numerous stands of western larch, Larix occidentalis, on the St. Joe, Coeur d'Alene, and Kaniksu National Forests, Idaho, show signs of gradual deterioration following repeated defoliation by larch casebearer, Coleophora Zaricella Hbn. (Tunnock et al. 1969). Stand deterioration can occur after 4 years of continued heavy defoliation. The main symptom...
The pine butterfly, Neophasia menapia Feld., has been at epidemic levels in the Bitterroot and Missoula valleys for the past 2 years (Ciesla et al. 1971) (Bousfield and Meyer 1972). Several reports of conspicuous pine butterfly flights on the Flathead Indian Reservation prompted an evaluation of the potential for pine...
The mountain pine beetle, Dendroctonus ponderosae Hopk., infestation advanced north and eastward from the 1971 infestation boundary in Yellowstone National Park. Infested trees were found in Indian Creek Campground at the north end of the park and around the north end of Yellowstone Lake. A ground survey showed an average...
Stepwise multiple regression techniques were used to statistically analyze the relationships between damage caused by the pine needle sheath miner Zellaria haimbachi (Busck); a needle miner, Oenerostoma etrobivorum (Zeller); sugar pine tortrix, Choriatoneura Zambertiana (Busck); and ambient and foliar concentrations of fluoride in lodgepole pine (Pinue contorta v. Zatifolia Engelm.)...
Aerial application of mexacarbate and Bacillus thuringiensis Berliner was tested against pine butterfly, Neophasia menapia (F. and F.). These were applied to 40-acre plots on the Bitterroot National Forest and adjacent State and private lands during June 1973. Two concentrations of each material were tested; these were 0.15 and 0.30...
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...
A study was conducted in summer of 1973 to assess impact of fluoride-insect damage on radial growth of lodgepole pine near the Anaconda Aluminum Company at Columbia Falls, Montana. Statistically significant growth losses attributed primarily to the effects of fluorides were found in 40 14 of 17 unmanaged stands for...
Aerially visible defoliation by the western spruce budworm, Choristoneura occidentalis Freeman, increased from 149,250 acres in 1973 to 649,319 acres in 1974 on five eastern Montana National Forests. An egg mass survey during the fall of 1974 predicted that additional defoliation will occur in 1975 on 47 of 48 plots...
The mountain pine beetle infestation has been epidemic in lodgepole pine in Yellowstone National Park since 1966. Infestation boundaries have advanced steadily northward and eastward. The infestation now encompasses nearly one-half of the total Park area. Surveys indicate a decline in tree mortality the last 2 years. In 1970, an...