Herbicides were tested for the selective control of bentgrass in
Kentucky bluegrass turf under three levels of competition. Best control
in zero competition was obtained with a winter treatment of
bromacil at two pounds per acre. Under circumferential and direct
competition, best control was obtained with a summer and fall...
Previous work has shown that diuron (3-(3, 4- dichlorophenyl)-1,
1-dimethylurea) is less toxic to fall-planted wheat than to wheat
planted in the spring. Diuron has been a significant factor in increasing
yields of winter wheat grown in Oregon's Willamette Valley.
The influence of several selected environmental factors on diuron
toxicity...
Marah oreganus, a perennial, belongs to the Cucurbitaceae family
and it is commonly known as wild cucumber. In the past, this plant
grew along fence rows, but now wild cucumber has become a weed
problem in perennial grass seed fields of western Oregon. Several
research studies were conducted to examine...
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...
Seed moisture is a primary factor influencing seed quality during harvesting, storage, and marketing of grass seed. However, the Association of Official Seed Analysts' Rules for Testing Seeds do not contain methods for moisture testing. The oven methods in use by seed testing laboratories in the U.S. are diverse and...
A vegetation study was made of four coastal marshes near Juneau,
Alaska. Results confirmed earlier studies' findings in southeast
Alaska that communities or assemblages of species can be identified
but from marsh to marsh these assemblages appear to have no consistent
relationship to each other or to environmental "factors" such...
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 %...
Field studies were started at Hyslop Farm, Corvallis,
Oregon in 1984 to determine the soil persistence of the
herbicide clopyralid (3,6-dichloropicolinic acid) under
cropping situations. The herbicide was sprayed on bare soil
at the proposed use rate of 0.14 kg/ha in the spring and on
the same plots at a...
Models of weed communities aid in the development of
weed management strategies and elucidate the processes
and mechanisms that regulate plant populations and
communities. A conceptual weed community model was
developed to organize key regulatory life-history
processes. Specific investigations focused on the
processes of plant growth and competition, and
relationships...
This thesis consists of four chapters. Literature is
reviewed in Chapter 1. Chapter 2 describes an addition
series experiment to determine the influence of species
density and proportion on vegetative and reproductive yield
of spring wheat and Lolium multiflorum. Chapter 3 consists
of a growth analysis experiment to determine whether...
Salmonberry (Rubus spectabilis) and thimbleberry
(Rubus parviflorus) are clonal shrub species common to
reforestation sites in the Oregon Coast Range. These
species have economic importance, because they reduce
conifer seedling growth and survival. A population modeling
approach was used to facilitate study of the biology of
these species and to...
Computer decision aids can help integrate and apply diverse sources of information and expertise to problems of integrated pest management (IPM) in agriculture and forestry. AppleMgr combines a rule-based expert system with databases and spreadsheets in a prototype decision aid intended to be expanded and modified for use by extension...