Previous work indicated a substantial heterotic expression for grain yield existed within winter/spring hybrids of barley, This research was a continuation for the comparison of the expression of heterosis within winter/spring hybrids to the heterotic effect produced among the winter and among the spring parents. The F₁ and F₂ progenies...
Trace metals in the aquatic environment are generally concentrated
on the surface of solid geochemical phases which eventually become incorporated
into estuarine and marine sediments. The mechanism of trace
metal concentration is believed to be adsorption with various geochemical
phases such as hydrous metal oxides, clays, and organic matter.
Metals...
A modified slide-dip bioassay was used to survey and establish
baseline resistance levels in Psylla pyricola Foerster from
western Oregon orchards to four pesticides. Orchards selected in the
Hood River, Rogue River and Willamette Valleys spanned a wide range of
environmental and management conditions. During the study period of
1982-1983,...
Tanoak (Lithocarpus densflorus (Hook and Am.) Rehd.), an evergreen hardwood tree that grows abundantly in southwest Oregon and
north California, sprouts vigorously after a disturbance, such as logging or fire These sprouts form clumps that can hamper conifer
regeneration on clearcuts and in shelterwoods. In order to obtain a quantitative...
Effects of tanoak (Lithocarpus densiflorus) on early
growth, morphology, and physiology of Douglas-fir
(Pseudotsuga menziesii) were studied to determine
developmental characteristics of young stands and
mechanisms of competition. Growth, leaf area, and biomass
of Douglas-fir, tanoak, and shrubs / herbs were monitored
for six years after establishing a gradient of...
Benomyl, a systemic benzimidazole fungicide was
incorporated into artificial diet and evaluated for its
oral toxicity to nonparasitized and parasitized third
instar orange tortrix larvae, Argyrotaeniae citrana
(Fernald) and its food chain toxicity via the host to the
solitary braconid endoparasite Apanteles aristoteliae
Vierek.
Concentrations of benomyl ≤ 300 ppm...
In the Pajaro Valley near Watsonville, California,
twospotted spider mite (Tetranychus urticae Koch)
populations were surveyed in 1983 and '84 to detect the
influence of immigrants from nursery plants or
surrounding vegetation on subsequent resistance
development to cyhexatin and formetanate in strawberry
fields. Susceptible mites (cyhexatin LC50 = 0.0039 %...
Documentation of the side effects of pesticides on
arthropod natural enemies has expanded rapidly since the
1950's as part of an increase in non-target side effects
literature. Most reviews have been based on empirical
analysis of selected literature. The SELCTV database was
developed to make a larger information base accessible...