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...
Causes of mortality of containerized western larch seedlings at the Champion Timberlands Nursery, Plains, Montana, were investigated. Seedlings were rated for disease severity based on extent of foliar decline symptoms and fungal isolations made from their roots. Isolations were also made from selected larch seed. Consistent associations between root colonization...
Needlecast caused by Meria laricis caused serious losses of 2-0 bareroot western larch during 1983 at the USDA Forest Service Nursery, Coeur d'Alene, Idaho. Cool, wet weather throughout the spring and summer of 1983 was ideal for disease buildup and spread. Control attempts with fungicides were largely unsuccessful because of...
This bulletin is one of a series on organic potato production developed by “OSPUD.” OSPUD is a collaboration among Oregon State University personnel and 11 farmers operating diversified organic vegetable farms. The purpose of OSPUD is to improve potato quality and profitability through a participatory learning process and on-farm, farmer-directed...
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...
The attack spatial pattern of the Douglas-fir beetle, Dendroctonus
pseudotsugae Hopkins was shown to be regular within a given subarea
of bark on its host, Pseudotsugae menziesii (Mirb.) Franco. Empirical
arguments were advanced which indicated the uniform spacing of attacks
was the result of a beetle controlled spacing mechanism dependent...
Felled second-growth Douglas-fir trees in western Washington were used
to determine the attack distribution and develop a sampling technique
for an endemic Douglas-fir beetle, Dendroctonue peeudotaugae Hopk.
(Coleoptera: Scolytidae) population. The attack density varied by
circumferential position. The lowest density was on the upper bole
and the highest on one...
Dwarf mistletoes, obligate, parasitic plants with diminutive aerial shoots, have long-term effects on host tree water relations, hydraulic architecture, and photosynthetic gas exchange and can eventually lead to tree death. To investigate the long-term impacts of dwarf mistletoe on gas exchange of host western hemlock trees, I compared growth, gas...