A series of studies was conducted to determine the presence
of tobacco rattle virus (TRV), potato virus X (PVX), and other
viruses in wild plants and to evaluate the efficacy of the detection
methods; to characterize and purify an isolate of TRV; and
to study the interaction between TRV and...
Field studies were conducted in 1973 and 1974 to determine the
soil persistence of the herbicide M-3785 (containing 0.5 lb a.e.
Dowco 290 + 2.0 lb a.e. 214D/gallon). under cropping situations.
Spring barley (Hordeum distichon L. 'Hannchen') was grown at
Corvallis, Oregon and winter wheat (Triticum aestivum L. 'Nugaines.')
was...
Studies were conducted to determine the nature of the interaction
between atrazine (2-chloro-4-ethylamino-6-isopropylaminos-
triazine) and magnesium on tomatoes. This interaction was
studied under two light regimes: continuous light and a 12-hour
photoperiod. Tomato plants were grown in sand cultures at three
levels of magnesium fertilization. Four weeks after planting,
atrazine...
Nine experiments were conducted during 1964 and 1965 to study
the methods of reproduction and mode of spread of sago pondweed
(Potamogeton pectinatus) in irrigation systems.
Frequent treatments of sago pondweed foliage with aromatic
solvent greatly reduced the number of tubers in the substratum of
an irrigation canal. However, complete...
The persistence of DCPA, trifluralin, diphenamid, diuron, and
prometryne was studied in three soils which were located at the Kula,
Poamoho, and Waimanalo Experiment Stations. The order of decreasing
persistency was diuron, prometryne, trifluralin, DCPA, and
diphenamid.
Diuron and prometryne activities were recorded for at least six
months and diuron...
Lateral diffusion of S-ethyl N-ethylthiocyclohexanecarbamate
(cycloate)¹ is essential for satisfactory weed control with injection
type incorporation in sugar beet (Beta vulgaris Linn.) production.
Previous field experience with injection incorporation has indicated
that sufficient lateral diffusion for satisfactory weed control has not
occurred under all field conditions. Researchers who have been...
Several studies were conducted to determine if a more consistent
predictor of phytotoxicity to winter oats could be obtained with a
surfactant-herbicide ratio or a per-unit-volume concentration of surfactant,
independent of volume. The herbicides tested were 2,2-dichloropropionic acid (dalapon), 1,1'-dimethyl-4, 4'-bipyridinium
(paraquat), and 3-tert-butyl-5-chloro-6-methyluracil (terbacil) with
the nonionic surfactant X-77...
Atrazine is an asymmetrical s-triazine herbicide used pre-
and post emergence for weed control in many crops. Triazine herbicides
have been used in the Pacific-Northwest for weed control in
orchard crops. Under certain conditions where trees were grown
in nutrient deficient areas, it was noted that toxic symptoms due to...
The use of bromoxynil (3,5-dibromo-4-hydroxybenzonitrile)
to control broadleaf weeds in cereal crops has become widespread.
This herbicide has not always performed satisfactorily for reasons
which were not clearly evident.
The effects of temperature, light and humidity on the herbicidal
activity of bromoxynil on coast fiddleneck, Amsinckia intermedia,
were studied. Fiddleneck...
Previous research has indicated several soil-applied herbicides
are more effective by exposure to emerging shoots than from
root uptake. Studies were conducted in the greenhouse and growth
chamber to investigate effects of herbicide placement in soil on
toxicity to emerging seedlings.
In these studies, an inch of treated soil was...
The influence of certain environmental and edaphic
factors on the germination and emergence of downy brome
(Bromus tectorum L.) was investigated in the laboratory. A
preliminary study was conducted to determine the osmotic
stability of mannitol and polyethylene glycol 20,000 (PEG)
solutions, which are commonly used to simulate water stress...
HOE 23408 [ 4-(2' , 4'-dichlorophenoxy)-phenoxy-u-propionic
methylester.1 is a promising new compound for control of wild oats
and other grass weeds in small grains. Several factors influencing
its use for this purpose were investigated.
Greenhouse bioassay studies were conducted in 1975 to determine
relative persistence of HOE 23408 in four...
Greenhouse and growth chamber experiments were conducted with
the following objectives: (a) to study the effects of N-1-naphthylphthalamic
acid (naptalam) on shoot and tuber production, rhizome transformation,
and growth of yellow nutsedge (Cyperus esculentus L.) plants;
(b) to study the effects of N-phosphonomethyl glycine (glyphosate) on
nutsedge plants at different...
Glyphosate (N-(phosphonomethyl)glycine) is an effective
foliar-applied herbicide with broad-spectrum activity. Greenhouse
and laboratory experiments were conducted to determine the
importance of soil moisture, autoclaved soil, soil type, sphagnum
peat, soil pH, added phosphorus, and plant residues on crop
establishment and growth when glyphosate was applied before
emergence of the crop....
After nearly 20 years of commercial use in orchards without
apparent tree injury in Oregon and Washington, 2,4-D [(2,4-dichlorophenoxy)
acetic acid] was reported in 1970 to cause injury to apple
and pear trees in Washington. In the early 1970's, there was widespread
concern among growers, researchers, and processors in the...
The use of terbacil for weed control was adapted by a high percentage
of Oregon peppermint growers soon after its introduction in
1967. To help clarify some of the implications of terbacil usage,
three studies were undertaken to collect information concerning (a)
the movement and build-up of terbacil in various...
Napropamide [2-(alpha-naphthoxyl)-N,N-diethylpropionamide], a
preemergence herbicide, is widely used in the United States on a
variety of tree fruits, nut crops, vegetables, and mint for annual
grass and broadleaf weed control. When napropamide has been left on
the soil surface without incorporation through irrigation or mechanical means, inconsistent results have been...
Studies were conducted to determine the extent and nature of
sub-lethal effects of herbicides on plant growth. At least one
herbicide from each major chemical class of herbicides was evaluated
under greenhouse conditions. Oat plants were grown in sand
culture to eliminate soil interferences. Herbicides were applied
pre-emergence in nutrient...
The herbicide rate required to reduce growth by 50% (GR₅₀) of 11
cultivars of red fesue (Festuca rubra L. and F. rubra ssp. commutata)
and for four cultivars of bentgrass (Agrostis tenuis Sibth. and A.
stolonifera L. var. palustris) to sethoxydim (2-[1-(ethoxyimino)
butyl]-5-[2-(ethylthio)propyl]-3-hydroxy-2-cyclohexen-1-one) was
determined in greenhouse and laboratory experiments....
Volunteer winter wheat (Triticum aestivum 'Daws')
severely suppressed growth of fall-planted alfalfa
(Medicago sativa (L.) 'Vernal') seedlings. Wheat
competition began soon after alfalfa emerged and continued
until the first forage harvest the following May. Alfalfa
yield at the first cutting was reduced by 1% for each day
volunteer wheat was...
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...
Eight postemergence herbicides were evaluated to determine
their influence on the incidence and severity of take-all disease
caused by the fungus Gaeumannomyces graminis var. tritici in winter
wheat. Mecoprop ((+)-2-(4-chloro-2-methylphenoxy)propanoic acid),
difenzoquat (1,2- dimethyl- 3,5- diphenyl -1H- pyrazolium), dinoseb amine
(amine salt of 2-(1-methylpropy1)-4,6-dinitrophenol), and diclofopmethyl
(methyl ester of (+)-2-[4-(2,4-dichlorophenoxy)...
Norflurazon [4-chloro-5-(methylamino)-2(3-(trifluoromethyl)
phenyl)- 3(2H)- pyridazinone] and prodiamine (N3, N3-di-n-propy1-2,4-
dinitro-6-(trifluoromethyl)-m-phenylenediamine) are two herbicides
being considered for weed control in alfalfa. Rotational crops
following alfalfa may be sensitive to residues of these herbicides.
Studies were conducted in Oregon and Washington to examine the soil
persistence and activity of these herbicides on...
A series of experiments were conducted from 1983 to 1985 to
determine the effects of dinoseb [2-(1-methylpropyl)-4,6-dinitrophenol]
on winter wheat (Triticum aestivum L. em Thell) yields. Field trials
on dinoseb timing and dinoseb plus supplemental pesticides were
established in an effort to elucidate the possible factors involved in
the yield...
Living mulches are vegetative covers that can grow in association with row crops and may prevent soil erosion and suppress weeds. Crop reduction from association with the living mulch is a frequent problem with this cultural practice. The interference between a white clover (Trifolium repens L. "New Zealand") living mulch...
The interference of barnyardgrass (Echinochloa crusgalli),
pigweed (Amaranthus retroflexus),downy brome (Bromus
tectorum),and tumble mustard (Sisymbrium altissimum)
with alfalfa was studied. Alfalfa was seeded with each of
the four weeds on August 14 and September 15, 1981, and on
April 13, 1982. Alfalfa also was seeded on August 27, 1981,
with...
Previous studies have shown loss of ethofumesate activity when
the herbicide was applied to dry soil (2% w/w moisture content) in
both field and greenhouse studies, even when rainfall or irrigation
was received within a few days. Laboratory studies were conducted to
determine the mechanism for this activity loss. Dry...
Investigations were made in the field, greenhouse, growth
chamber, and laboratory to: (a) observe the general activity of N-
(phosphonomethyl)glycine (glyphosate); (b) determine the extent of its
interaction with certain s-triazine herbicides; and (c) find an explanation
for such an interaction.
Greenhouse and growth chamber studies substantiated other
observations that...
Several studies were conducted to determine the effect of weed
density on herbicide efficacy. Diuron [3-(3, 4- dichlorophenyl) -1, 1-
dimethylurea] was tested on various densities of Italian ryegrass
(Lolium multiflorum Lam. ) under greenhouse and field conditions.
Cycloate (S-ethyl N-ethylthiocyclohexanecarbamate) was tested on
green foxtail (Setaria viridis (L. )...
In previous research, bromacil gave good performance when
it was applied in early fall with fairly dry soil conditions and before
the fall germinating weeds had started growth. On the other hand,
if bromacil was applied in late November, December, or January
on nearly saturated soil with weeds that had...
Previous field research with terbacil (3-tert-butyl-5-chloro-
6-methyluracil) has shown that early fall applications to dry soil
performed better than did late fall or early winter applications to
wet soil. Field and greenhouse studies were conducted to determine
the effect of soil moisture content at time of application and the
effect...
Norbak, Dacagin, and Vistik, when mixed with a spray solution,
each have the unique property of increasing the viscosity of
that solution. This property has been used commercially for the
reduction of spray drift.
Studies were made of the drift control adjuvants to determine
the following: (1) the effect of...
Liming has been shown to increase the activity of certain soil-applied herbicides. One research worker reported improved weed control with diuron after lime had increased soil pH levels. This could be caused by improved competitive ability of the wheat, greater availability of the herbicide, or a combination of the two...
Studies were conducted to verify the existence of IAA in wheat
seedlings and to determine the effect of (2-chloroethyl)-trimethyl-ammonium
chloride (CCC) on the IAA content of club wheat,
Triticum aestivum compactum, variety Omar. The shoots of CCC-treated
and untreated wheat plants were extracted with ethanol, the
plant extract purified, separated...
This study was conducted to compare the effectiveness of four
methods of incorporating the herbicide trifluralin into the soil, and
to determine the interaction between depth of incorporation of trifluralin
and depth of weed seed germination.
Field experiments on green and dry peas were established in
Oregon and Idaho. Trifluralin,...
Laboratory and field studies were conducted at Pendleton, Oregon, during 1983 and 1984 to evaluate germination and growth characteristics of five jointed goatgrass (Aegilops cylindrica Host) accessions collected from sites in Echo, Ione, Pendleton, Condon, and Elgin, Oregon. Spikelets were germinated for 27 days at room (23 +̲ 2 C)...
HOE 23408 [methyl 2-[ 4-( 2, 4- dichlorophenoxy )phenoxy]propanoate]
is a herbicide used to selectively-control Italian ryegrass
(Lolium muitiflorum Lam.) and wild oats (Avena fatua L.) in wheat.
The objective of this research was to compare the relative importance
of foliar and root uptake of the herbicide in these two...
Several studies were conducted to determine the feasibility of
using terbacil (3-tert-butyl-5-chloro-6-methyluracil) postemergence
to weeds and peppermint (Mentha piperita L.). Three nonionic surfactants,
four nonphytotoxic oils, and a liquid fertilizer were each
combined with 0.5 lb ai/A terbacil in 35 gallons of water per acre.
Weed species tested include: redroot...
Studies were conducted in 1969 and 1970 to evaluate the
effectiveness of an experimental herbicide, SD 30053 (alanine,
N-benzoyl-N-(3, 4-dichlorophenyl)-, ethyl ester), for wild oat
(Avena fatua L.) control in winter cereals.
The 1969 field studies showed that postemergence applications
of SD 30053 were effective in controlling wild oats. Wild...
The purpose of this study was to evaluate the activity of Sindone (isomers of 1, 1-dimethyl-diisopropyl-indanyl ethyl ketone) under field conditions and to gain information regarding the rate of detoxification of Sindone in soil. A series of trials were established in sugar beet fields in California, Oregon, and Washington. Sindone...