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...
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...
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...
Western spruce budworm defoliated area in the Northern Region has differed significantly across three discrete geographic zones during the past decade. Aerially visible defoliation in northern Idaho increased from 1.7 million acres in 1969 to a high of 2.2 million acres in 1974, and declined to none in 1979. Defoliated...
A needle miner, Coleotechnites sp., defoliated approximately 3,100 acres of ponderosa pine, Pinus ponderosa Laws. on the Flathead Indian Reservation, Montana, during 1978. Three other small areas in the Missoula Valley were infested also. Overwintering populations of larvae are low; thus, light defoliation is expected in 1979 in presently infested...
The forest tent caterpillar, Malacosoma disstria Hbn., began defoliating trembling aspen stands, Populus tremuloides Michx., in 1976 in the Turtle Mountains of North Dakota. Heavy defoliation was scattered through about 150,000 acres in 1978. Pupal mortality from parasites and disease was almost 100 percent in cocoons on understory shrubs and...
Aerial and ground surveys to detect and evaluate forest insect and disease conditions in North Dakota were made during June 1977 by personnel from the U.S. Forest Service, Forest Insect and Disease Management staff and the Rocky Mountain Forest and Range Experiment Station. A forest tent caterpillar outbreak in the...
A pilot project to evaluate trichlorfon and acephate for suppressing western spruce budworm populations was conducted on the Helena National Forest, Montana. Both insecticides were applied at 1 pound active ingredient per acre. Application was made with a Bell 205A helicopter using eight Beecomist Model 350 spray heads. Treatments and...
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...
Aerial surveys of six Montana National Forests in 1975 found a 22.1% increase in the area of visible defoliation caused by the western spruce budworm. It is estimated that 2,278,804 acres of Douglas-fir forests are now suffering at least 25% defoliation. This is an increase of 503,706 acres over the...
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...
A supplemental Douglas-fir tussock moth egg mass evaluation was made within three quarter sections north of Poison, Montana, during April 1975. These areas were being considered for a pilot control project of a nucleopolyhedrosis virus spray. Results from the April evaluation showed these areas no longer qualified as sites for...
In 1973, two centers of defoliation by Douglas-fir tussock moth totaling 350 acres were detected near Missoula, Montana. Egg mass surveys showed two sections south of Frenchtown and one section northwest of Lolo 41, contain sufficient egg mass population to cause heavy defoliation in 1974.
Evaluation of Douglas-fir tussock moth, Orgyia pseudotsugata, egg masses collected from an outbreak area in the lower Flathead Valley indicated that overall egg viability was relatively high, egg parasitism was low, and virus infestation averaged 7.1 percent northwest of Polson, 17.9 percent south of St. Ignatius, and 57.0 percent west...
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...
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...
An aerial survey during 1974 revealed approximately 5,000 acres of various degrees of Douglas-fir tussock moth, Orgyia pseudotsugata McD., defoliation in the lower Flathead Valley. An egg mass survey was made in September to determine the potential for damage in 1975. Based on new egg mass densities, significant defoliation may...
An epidemic of Douglas-fir tussock moth was detected in northern Idaho
in 1972. In 1973, aerial surveys showed that nearly 100,000 acres contained
various degrees of visible defoliation. An egg mass survey of
five reporting units made in the fall of 1973 determined potential for
damage in 1974. Based on...
An active infestation of ash borer, Podosesia syringae (Harris) was detected in green ash, Fraxinus pennsylvanica Marsh, surrounding the Bowman-Haley Reservoir in 1973. A survey in 1974 showed that 40.4 percent of 690 trees examined contained active ash borer attacks. Forty-three out of 140 windbreaks were sampled and each one...
Douglas-fir tussock moth egg mass studies during winter 1974 indicate that natural factors such as low egg viability, egg parasitism, and virus do not alter the potential for heavy defoliation in two sections south of Frenchtown and one section northwest of Lolo, Montana.
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.
An evaluation was made during midsummer 1972 to measure damage by the carpenterworm, Prionoxystus robiniae, and the ash borer, Podosesia syringae, to green ash in windbreaks in North Dakota. Intensity of infestation was determined in four land resource areas and four age classes of windbreaks. Of the 96 windbreaks examined...
The Douglas-fir tussock moth, Orgyia pseudotsugata McD., periodically
defoliates Douglas-fir, true firs, and other host trees in forests of
the western United States. In the Northern Region, these infestations
occur about once every decade.
This history covers the earliest recorded outbreak in northeastern
Washington from 1928 to 1930 and includes...
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...
The last outbreak of the Douglas-fir tussock moth, Hemerocampa pseudotsugata McD., in the Northern Region subsided in 1965. Tussock moth populations were not detected again until 1970 when ornamental spruce were defoliated in Spokane, Washington, and Poison and Missoula, Montana.
An attempt was made in January 1971 to relate the numbers of hibernating western spruce budworm larvae on a square foot of bark surface with subsequent shoot damage on Douglas-fir and grand fir in northern Idaho.
Twenty-six plots sampled in January were also sampled in April to determine
if larval...
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...
A study was made to determine the distribution of parasites of the larch casebearer, Coleophora laricelia, within crowns of western larch, Larix occidentalis. The most common parasites recovered in order of their abundance, were: Agathis pumila (Ratz.), Diciadocerus sp. near westwoodii, Spilochalcis albifrons (Walsh), and MesopoZobus sp. Parasitism by A....