This study evaluated the effects of tillage system, rotational tillage sequences, and winter seed burial depth on weed seedling recruitment in irrigated cropping systems. Notill (NT) planting of vegetable crops reduced emergence of hairy nightshade by 77 to 99% and Powell amaranth emergence from 50 to 87% compared to conventional...
Wild proso millet (Panicum miliaceum L.) is a serious weed
recently infesting sweet corn fields in the Willamette Valley of
western Oregon. Field and greenhouse experiments were conducted to
determine the importance of seed depth in the position of the growing
point of wild proso millet seedlings and in the...
The dynamics of tansy ragwort, Senecio jacobaea L. , and the cinnabar moth, Tyria jacobaeae (L.) were studied with the aid of a system simulation model. The model development and validation were based on knowledge of the plant and herbivore gathered from the literature, four years of data from previous...
Hand-defoliation was evaluated for its ability to
simulate herbivory by cinnabar moth larvae, Tyria
jacobaeae (L.) (Arctiidae) on the weed tansy ragwort,
Senecio jacobaea L. (Asteraceae). The evaluation was done
on a field population of flowering ragwort, for three
different timings (early, middle, and late season) of
damage.
In the...
To determine which isolates will most rapidly replace
Phellinus weirii in stumps and roots, Trichoderma spp. were
isolated from P. weirii-infested stumps and roots, identified, and
examined for growth rates and lethal effects on P. weirii in vitro.
Phellinus weirii-infested Douglas-fir stumps and stump roots
were sampled for microorganisms by...
Laboratory studies were conducted to evaluate the effects of prey
availability on prey consumption, survivorship and oviposition of the
southern pine beetle predator, Thanasimus dubius Fabricius. Although
prey consumption rates were significantly affected by the sex, size and
ovipositional status of the predator, it was found through correlation
analyses that...
A classical biological control project was undertaken
against the filbert aphid, Myzocallis coryli (Goetze), in
western Oregon. Hazelnut orchards in Spain, France, and
Italy were searched for natural enemies of the aphid, and
a parasitic wasp, Trioxys pallidus Haliday, was imported,
quarantined, mass-reared, and released in Oregon orchards.
The wasp...
We identified and evaluated a phytoseiid predator as a biological control agent of multiple spider mites pests that occur in ornamental nurseries. When comparing species, Neoseiulus fallacis (Garman) had a wider prey range than Galendromus occidentalis (Nesbitt), a higher probability of overwintering than Neoseiulus califomicus McGregor and was equally or...
Published June 1991. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog