Four key aspects of the relationship between predatory hoverflies and the aphid pest Brevicoryne brassicae L. on broccoli were investigated in the Willamette Valley, Oregon USA: 1) the relationship between aphid density and hoverfly oviposition, 2) the larval voracity of key hoverfly species, 3) the preferences of hoverflies and broccoli...
Published February 1925. 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
Preservation of rare plant species often requires establishment of new populations. Survivorship surveys are the most common method of post-introduction monitoring. However, they provide an incomplete picture of establishment success. This study is an attempt to develop a model for determining establishment success by determining the factors affecting recruitment in...
Nitrogen management recommendations for yellow mustard (Sinapis alba L.) production in the high rainfall environment of Oregon's Willamette Valley (WV) are not available. The objectives of this investigation were: (i) to determine the effect of applied nitrogen (N) on seed yield and yield components in yellow mustard, and (ii) to...
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...
Commercial radish seed producers in the Willamette Valley of Oregon have observed a late season wilt in their seed fields. Twenty-two fields were surveyed for wilt in the Willamette Valley during June through August 2012 and 2013. Plants exhibiting wilt symptoms were collected from the fields and examined for vascular...
This thesis is a documentation of a selected number of nineteenth century quilts studied by the investigator in the Willamette Valley.
The quilts were located in museums and in individual's homes. A questionnaire, that was developed for this study of quilts, was
filled out as each quilt was examined. Slides...
The future expansion of agricultural production in the Willamette
Valley will depend to a large degree upon the feasibility of introducing
irrigated agriculture on the poorly drained soils in the Valley. A
r earch program has been initiated to investigate the feasibility of
rigation on poorly drained soils with the...