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....
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...
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...
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.
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 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...
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...
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.