An experimental formulation of 9 -oxodec-trans-2-enoic acid, the major component of honey bee (Apis mellifera L.) queen pheromone, was tested for its effect on worker foraging behavior in the pollination of sweet cherries (Prunus avium L. ). The test formulation consisted of a solid beeswax cylinder impregnated with a measured...
This study describes and quantifies some microprocesses of malaria
transmission including blood vessel location by Anopheles stephensi and
sporozoites delivery of An. stephensi infected by Plasmodium berghei. The
study models the effects of malaria parasite-induced changes in probing
behavior and mosquito mortality on disease transmisson. Finally, host, vector,
and parasitological...
The eruption of Mt. St. Helens provided the
opportunity to study secondary production of grazing insects in the context of disturbance. Two stream sites were chosen that significantly differed in how their
watersheds were impacted by the eruption. Clearwater Creek was catastrophically disturbed (physical alteration of habitat, loss of riparian...
Verticicladiella wageneri Kendrick is a vascular wilt
pathogen of conifers, causing a black staining of
colonized sapwood of roots and lower stem. In Douglas-fir,
V. wageneri is intimately associated with insects.
Hylastes nigrinus, Pissodes fasciatus, and Steremnuis
carinatus are commonly associated with diseased hosts,
carry inoculum of V. wageneri in...
Epichloë typhina (Ascomycetes: Clavicipitaceae) is an endophytic fungus that
infects perennial Pooid grasses and is the causal agent of choke disease. It is endemic
to Europe and was inadvertently introduced into orchardgrass seed production fields in
western Oregon. Choke disease, which was first recorded in Oregon in 1996, currently
infects...
The seasonality, relationship of temperature and
photoperiod to growth and post-diapause development, and
overwintering behavior of codling moth, Cydia pomonella L.,
(Lepidoptera: Olethreutidae) were studied over a three year
(1986-1989) period. The developmental threshold varied from
a low of 9.66°C for the second instar to a high of 14.23°C
for...
The effect of anthropogenic disturbance on river systems is gaining attention, and concerns about the state of freshwater natural resources are increasing globally, as are efforts to restore habitat that has been degraded by disturbance. In rivers, non-point source pollution affects the physical characteristics of the habitat and the endemic...
The predatory mite Typhlodromus pyri (Acari: Phytoseiidae) is the predominant species in cool climate Pacific Northwest vineyards and a principal predator of pest mites including the grapevine rust mite Calepitrimerus vitis (Acari: Eriophyidae). In recent years vineyards have been experiencing C. vitis population outbreaks leading to increased economic damage from...
Invasive plants have the potential to reduce the diversity of species in plant and animal communities. I examined the negative effect of two invasive wetland plants, purple loosestrife and reed canary grass, on the species richness and diversity of plant and moth communities within 24 wetland study sites in the...
Purple loosestrife is a wetland perennial that came to the eastern seaboard of
North America in ship ballast and raw wool in the 1800's. Since coming to the
United States, it has spread across the country, forming dense monospecific stands
in wetlands. Mechanical and chemical control was expensive and ineffective,...