Controlled flow reductions of 75% apportioned over
four two-week intervals were studied during the summers of
1975 and 1976 on the North Fork of Elk Creek, an Oregon
coastal stream. The effects of reduced flows on invertebrate
drift, insect benthos, and the available food for
juvenile salmonids were measured.
Invertebrate...
Three sympatric species of Ips, colonizing Sitka spruce, were
investigated with regard to their infestation habits, stridulating
apparatus and acoustic signals. The above phenomena are evaluated
qualitatively and/or quantitatively and the acoustic signal differences
are proposed as a possible factor for maintaining species isolation,
although function is not shown.
Field...
Prothoracicotropic hormone has been partially purified
from whole heads of tobacco hornworm larvae, Manduca sexta.
Activity was followed with a larval bioassay. Activity was
purified 4400 fold from crude extracts. The hormone was
found to be a heat-stable polypeptide with an approximate
molecular weight of 25,000 Daltons. The hormone has...
Studies were conducted in the Willamette Valley of western Oregon to evaluate the effects of plowing (7.5-15 cm deep) and disking (5-10 cm deep) in peppermint, Mentha piperita L., on the following factors: 1) emergence of adult "mint root borer", Fumibotys fumalis Guenée; 2) suppression of common groundsel, Senecio vulgaris...
The known biology of Bareogonalos canadensis
(Harrington) is based on literature records of six
collections from three areas in the Pacific Northwest.
The objective of this study was to obtain fundamental
knowledge on the biology of B. canadensis, especially
its distribution, abundance, and host species, as well
as its potential...
Published November 1891. 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
Aggregation and species association of 9 species of phytophagous and
predaceous mites were studied for 6 yr in an orchard with 100, 2 m tall 'Red
Delicious' apple trees. To quantify aggregation, a method was developed that is
powerful, and easily interpreted. It relates the proportion of habitat occupied to...
The balsam woolly aphid (Adelges piceae (Ratz)), an
European pest of conifers, was first discovered in the
Pacific Northwest shortly after 1930. Control measures
of a chemical, silvicultural, or biological nature have
been proposed. However, present control methods are either
too costly or do not result in satisfactory control of...