The hemlock woolly adelgid, Adelges tsugae, is causing widespread mortality of eastern hemlock, Tsuga canadensis, in the eastern United States. In the West, A. tsugae causes negligible damage to western hemlock, Tsuga heterophylla. Host tolerance traits and presence of endemic predators may be contributing to the relative tolerance of western...
Hemlock woolly adelgid, Adelges tsugae Annand, is a serious threat to eastern hemlock, Tsuga canadensis Carriere, in the eastern United States. Infestations of A. tsugae are spreading rapidly and tree mortality caused by the insect is increasing yearly. As part of an integrated management approach, a classical biological control program...
Live western larch, Larix occidentalis Nutt., a tree species resistant to the Douglas-fir beetle, Dendroctonus pseudotsugae Hopkins, produces the monoterpene 3-carene in higher concentrations compared to Douglas-fir, the preferred host of D. pseudotsugae (Reed et al. 1986). The inhibitory effects on attraction to aggregation pheromones and toxicity of 3-carene to...
Three studies on Douglas-fir beetle (DFB), Dendroctonuspseudotsuae, were conducted to investigate its basic and applied biology. Studies included investigations into the spatial relationship of DFB infestations over multiple years and multiple landscapes, relationships between DFB brood adult lipid levels and position of development along the length of tree boles, and...
Concerns over the possibility of exotic pest
introductions from eastern Russia to the West Coast of the United States due to proposed log imports raises the question of the effectiveness of possible mitigation measures. Toxicity of methyl bromide to representative pathogenic fungi was tested by exposing Armillaria ostoyae, Heterobasidion annosum,...
The objective of this study was to determine how the
balance of carbon to nitrogen in a grand fir ecosystem affects
the chemistry of emerging grand fir foliage and the growth of
western spruce budworm larvae. Forest plots in the grand fir
zone of eastern Oregon were thinned, thinned and...
