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...
The genus Lopidea Uhler is revised for America north of
Mexico. The relationship of Lopidea to other orthotyline
genera is discussed and it is proposed that the genus
Ilnacora Reuter is the sister group of Lopidea.
Forty-eight species of Lopidea are recognized in North
America, one of which is described...
There are several grape disorders that reduce fruit
set. One, millerandage, is from poor fertilization to
produce "hen and chicken" or small seedless berries; while
another, Coulure, is the failure of grape flowers to
develop into berries. A third one, inflorescence necrosis
(INec), is a disorder that should be in...
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...
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...
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...
Sod-seeding techniques offer graziers a convenient way to introduce superior grass cultivars into underproductive permanent pastures. Production loss and erosion are minimized. In conjunction with improved grazing management and fertilization, renovation can significantly improve yield and quality of pastures. Existent vegetation must be suppressed prior to introducing new cultivars. This...
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...
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...
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...
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...
This study investigated some functional and
biochemical characteristics of a bacteriolytic protein in
the salivary glands of adult Aedes aecupti. A method for
the isolation of this protein from other mosquito salivary
gland components is also described. Based on some of its
biochemical properties, this bacteriolytic protein can be
classified...
Purple nutsedge [Cyperus rotundas L.) has been recognized as one of the
most troublesome perennial weeds of agricultural lands in tropical and some
temperate regions. This research sought to determine the effects of timing of
herbicides, shading, and soil moisture on plant population growth and tuber
production of purple nutsedge...
Juvenile Douglas-fir, ponderosa pine, and whiteleaf manzanita
growth in southwest Oregon varied with density of co-developing
manzanita and presence of herbaceous cover. Plant xylem pressure
potential and stomatal conductance of each species was responsive
to competition-induced depletion of soil water. Rates varied among
species. The best correlations with growth usually...
Nutrient losses of the biologically responsive anions, nitrate and bicarbonate together with the major cations, were monitored on 14 small watersheds in Oregon's Coast Range and evaluated in relation to management-induced disturbance. Mixed forests of Douglas-fir and red alder had dominated these high-nitrogen sites prior to treatment. A paired-watershed experimental...
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...
The Mimulus washingtonensis complex is a group of morphologically similar
species centered in the Pacific Northwest. All are rare, and most are under
consideration for listing as endangered. Morphometric and pollination data were
used in developing a revised taxonomy for the group. Five species and two varieties
are recognized. Mimulus...
Penetration of ¹⁴C-labeled plant growth regulators into the surface of apple
(Malus pumila M.) leaves pre-soaked in 10 ml I⁻¹ solutions of surfactant was
measured by detecting changes in radioactivity of the solution in glass cylinders
sealed to the astomatal, adaxial surface of the leaf discs. Penetration of 2,4-D
[(2,4-dichlorophenoxy)acetic...
Dormancy of 'Pinot Noir' grapevines was characterized. Primary buds
required ca 300 cumulative chilling hours (CCH) to initiate the transition from
endodormancy to ecodormancy, which occurred in mid November. Additional
chilling, up to 1000 CCH, improved budbreak. Changes in bud water content
were estimated by gravimetric and spectroscopic methods. Total,...
Most of the presently grown cultivars of rice (Oryza sativa L.) have poor
competitive ability against weeds if compared with traditional cultivars. Therefore,
effective weed control is an important but often costly and difficult management
practice in rice crop production. If weed competitive ability of rice cultivars could be
improved...
Temperate climates are particularly conducive to
growth of annual bluegrass which readily invades and
dominates most cool-season turfgrasses. Ethofumesate
(2-ethoxy-2,3-dihydro-3,3-dimethyl-5-benzofuranyl
methanesulfonate) is one herbicide available which will
selectively control annual bluegrass.
The primary objectives of this research were to
determine optimum application rates and timing of
ethofumesate for control of...
Relay strip-cropping combines two vegetation management tactics, under-sowing
and strip-management. In this study conducted from 1994 though 1997, a
cover crop seed-mixture containing oats (Avena sativa L. var. "Monida"), common
vetch (Vicia sativa L.), red clover (Trifolium pratense L.), annual ryegrass (Lolium
multflorum Lam.), and buckwheat (Fagopyrum esculentum Moench) was...
Profitable, even-aged forest management depends on the early establishment
and rapid growth of each new forest crop. These, in turn,
require that the young trees have access to an adequate supply of
native resources of moisture, nutrients and light. In Mediterranean-type
climates, competition for soil moisture is the most serious...
The use of chemicals such as the triazines (especially atrazine) and mixtures of the triazines and 2,4-D or 2,4,5-T has become almost standard practice in some parts of the world for selectively controlling grasses and other herbaceous weeds to conserve moisture for and/or prevent the smothering of newly-planted conifers. In...