A chronic infestation of mountain pine beetles in lodgepole pine in Glacier National Park, Montana

An infestation of mountain pine beetle (Dendroctonus ponderosae Hopk.) in lodgepole pine (Pinus contorta var. latifolia Engelm.) has been active since about 1950 in an area of 162 ha within Glacier National Park, Montana. Tree mortality is reported for 14 years. It fluctuated yearly, ranging from 0 to 4.7 trees per 0.405 ha (1 acre). Most trees above 25.4 cm in diameter had been killed by 1963

Evaluation of a forest tent caterpillar infestation south of Devil's Lake, North Dakota

In 1971, about 2,000 acres (Figure 1) of mixed hardwoods were infested by the forest tent caterpillar, Malacosoma disstria Hubner, on the Totten Indian Reservation south of Devil's Lake, North Dakota. An aerial and ground survey of this area was made on June 15, 1972. Defoliation could not be detected from the air, but very light feeding was evident on American basswood, Tilia americana L., and incidental feeding on American elm, UZmus americana var. americana, and chokecherry, Prunus virginiana L. The forest tent caterpillar was still feeding on June 15, but a few larvae were preparing to pupate. Diseased larvae were not apparent, and percent parasitism could not be determined at this time. This infestation has been decreasing since 1970, but there seems to be enough larvae in the 2,000-acre area to continue a low-level infestation in 1973. Because damage will probably be slight in 1973, no control is recommended

Evaluation of a hemlock sawfly outbreak in the northern tip of Idaho, 1985

A rare outbreak of hemlock sawfly, Neodiprion tsugae Middleton, was detected in August in drainages near the Canadian border in Idaho infesting several thousand acres. Some stands of western hemlock and subalpine fir were severely defoliated. Understory Engelmann spruce trees were lightly defoliated. The sawfly overwinters in the egg stage within current needles. Very few eggs could be found during a survey in October. Some hemlock trees may be topkilled, but natural control agents usually cause these sawfly outbreaks to collapse in 1 or 2 years. No control action was recommended

Suppression of cranberry girdler damage in beds of Douglas-fir seedlings, Coeur d'Alene Nursery, Idaho Panhandle National Forest, 1984

The cranberry girdler, Chrysoteuchia toparia Zeller, has caused increasing damage to tree seedlings in the Coeur d'Alene Nursery since 1980. Heaviest feeding has occurred on the tap roots of 2+0 Douglas-fir stock. By 1983, 8.2 percent of the seedlings examined in seedbeds were injured by this moth. A spray program was adopted in 1984 to reduce the amount of damage. Three applications of Diazinon at 1 lb. active ingredient per acre were used to kill adult moths, and three applications of Dursban at the same rate were used to reduce larval populations in the soil of Douglas-fir beds. Results of the insecticidal treatments were determined in November 1984 during lifting operations. In sprayed beds, only 0.01 percent of the 2+0 Douglas-fir seedlings examined were injured, and 0.9 percent of the 3+0 Douglas-firs examined were injured. There were no beds of unsprayed Douglas-fir seedlings to use as a check. Because damage was 8.2 percent in beds during 1983, and moth populations were high in 1984, damage in unsprayed beds could have been 8 percent or greater in 1984. Nurseries consider damage tolerable when it is below 1.0 percent

Western spruce budworm egg masses for predicting defoliation potential in the northern region : progress report

An attempt was made to predict western spruce budworm defoliation using egg counts from plots in the Douglas-fir type east of the Continental Divide in Montana, the Douglas-fir type west of the Continental Divide in Montana, and the mixed grand fir Douglas-fir type of northern Idaho. The parameters used in a linear regression model for the three ecotypes were eggs per 100 buds in 1972 as the independent variable and percent defoliation in 1973 as the dependent variable. Correlation coefficients (0 were: 0.39, 0.54, and 0.66 for the data from grand fir in northern Idaho and Douglas-fir in eastern and western Montana respectively. A covariance analysis of the three regression lines showed there were differences between the three ecotypes

Potential for defoliation by western spruce budworm in northern Idaho and Montana, 1977

Epidemic populations of the western spruce budworm persist in the Northern Region. Aerial surveys made in August 1976 showed a decline in the acreage of aerially visible defoliation. In northern Idaho, the defoliated area dropped from 831,487 acres in 1975 to 655,711 acres in 1976, down 21 percent. Surveys in Montana found a net decrease in defoliation of 11 percent, down from 2,797,986 in 1975 to 2,496,274 in 1976. Egg mass surveys made in September and October 1976 indicate that defoliation will be light on the Clearwater and Nezperce National Forests and moderate on the Idaho Panhandle National Forests, Idaho, in 1977. Defoliation in Montana during 1977 is expected to be light on the Flathead, moderate on the Kootenai, and heavy on the Beaverhead, Bitterroot, Deerlodge, Gallatin, Helena, Lewis and Clark, and Lolo National Forests and the Flathead Indian Reservation

Survey of hardwood defoliation in the Turtle Mountains, North Dakota

A looper, probably the Bruce spanworm, Operophtera bruceata (Hulst), defoliated more than 15,650 acres of quaking aspen in the Turtle Mountains of North Dakota in the spring of 1973

Evaluation of larch casebearer parasites on the Flathead National Forest, Montana, 1985

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 (Ratzeburg), an exotic wasp that was established within the Flathead NF from 1967 to 1969