The shake and wash technique (samples placed in a jar with alcohol added and
shaken to remove the mites) was effective in removing 100% of the predator mites, and adult
spruce spider mites from Douglas-fir foliage and 98% of the spruce spider mite nymphs.
Eighty-eight percent of the spruce spider...
An investigation was conducted in 1980 and 1981 on the larval
parasitoid complex of the orange tortrix, Argyrotaenia citrana
(Fern.), a major contaminant in cane fruits (Rubus spp.) in the
Pacific Northwest. A total of 13 parasitoid species were reared from
1,350 larvae predominantly collected from red raspberries in western...
The twospotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), is a
worldwide pest of numerous agronomic and horticultural plants. Conservation
biological control of this pest can be unreliable due to asynchrony of natural enemies
and certain horticultural practices that have a direct or indirect affect on natural
enemies and the...
Some consideration has been given to the irrigation of winter
wheat in the Willamette Valley of Oregon. This important crop has
yielded quite well since the development and introduction of the
stiff-strawed, semi-dwarf wheats, but, because of the usually dry
early summers, it has been suggested that irrigation of winter...
Debris flows are a major cause of disturbance to riparian vegetation. Both observational and experimental studies were used to examine the initial recovery of riparian vegetation after debris flows on headwater streams in the western Cascades of Oregon. My goal was to determine the roles of seedlings and vegetative sprouts,...
Remote sensing techniques have long been useful in quantifying changes in ecosystems and the field of remote sensing is constantly evolving to better assess and describe changes, both spatially and temporally. In this thesis I explored the novel use of two remote sensing methods to quantify ecosystems; repeat photograph to...
Leafhoppers (Homoptera: Cicadellidae) were surveyed in Western Oregon vineyards in 1999. Four sites were sampled for leafhoppers using a sticky trap method, and 29 vineyards were sampled for leafhoppers using a sweep net method in the summer of 1999. The sticky trap and sweep net methods were chosen based on...
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...