In 1967, Lophodermella morbida Staley and Bynum, a recently described
hypodermataceous needle-cast fungus, became destructively
epidemic in a knobcone pine (Pinus attenuata Lemm.) plantation in
Del Norte County, California, and in several ponderosa pine (P.
ponderosa Laws.) plantations in western and southwestern Oregon.
This thesis presents information on this currently...
Self-interactions (effects of reinoculation with the same nematode)
in Meloidogyne hapla and Heterodera schachtii on Beta vulpris at
different levels of inocula with various population combinations were
studied. In M. hapla, the only significant increase of galls was
noted in treatments when 250+250 larvae were inoculated at 10-day
intervals. Longevity...
Studies were conducted on the mechanisms contributing to
resistance in broccoli, Brassica oleracea italica, to the garden
symphylan, Scutigerella immaculata (Newport). Differences in
resistance to symphylan injury were shown between five selected
broccoli cultivars. The hybrid cultivars, Crusader, Green Duke
and Bravo, showed a higher level of resistance to symphylans...
The seasonal development and habits of Labops hesperius Uhler
were studied in rangeland seeded to intermediate wheatgrass (Agropyron
intermediurn (Host) Beauv. ) in Baker County, Oregon, The
first nymphs appeared on March 22, and required about one week to
complete each of the five nymphal stadia. Most small nymphs stayed...
Footrot of wheat (Cercosporella herpotrichoides Fron) is a
major disease of winter wheat in certain areas of the world having a
cool, damp winter and early spring climate. In Oregon, it is an
economic problem in the higher rainfall wheat-growing areas in the
eastern portion of the state. This study...
Observations of bacterial soft rot of onions in the Lake Labish
area in the Willamette Valley of western Oregon showed that two distinct
symptom types occur during the growing season. The most
prevalent symptom type appears in infected plants as a wilting and
chlorosis of two or more lower leaves...
A series of field experiments was conducted during 1975 and
1976 to examine peppermint tolerance and Canada, thistle response to
Dowco 290 (3, 6- dichloropicolinic acid). Peppermint oil yield and
Canada thistle density were considered most important in evaluating
experimental results.
Peppermint tolerance to Dowco 290 was studied in weed-free...
Hop varieties were compared under field and greenhouse conditions to determine their relative susceptibility to the twospotted spider mite, Tetranychus urticac Koch. A fertility schedule was prepared for mites on resistant and susceptible varieties, and tests were conducted to compare sex ratio, oviposition rate, survival rate, and developmental rate of...