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...
Tuber oatgrass (Arrhenatherum elatius (L.) Presl. var.
bulbosum (Willd.) Spenn.) is a perennial grass that often
becomes a weed problem in Western Oregon. Control efforts
using glyphosate often give unsatisfactory results. The
effects of several factors on development of tuber oatgrass
were investigated. Long days and cool temperatures (16/8h,
20/10C...
Time-course growth chamber studies were conducted on little mallow
(Malva parviflora L.) to determine whether sublethal doses of lactofen
(1'-(carboethoxy)ethyl-5-[2-chloro-4-(trifluoromethyl) phenoxy]-2-
nitrobenzoate) would enhance uptake of glyphosate (N'-(phosphonomethyl)
glycine) by altering membrane permeability. Lactofen-induced membrane
peroxidation was determined by harvesting leaf discs, measuring stress
ethylene evolution, and recording increases in...
Growth of individual goosegrass (Eleusine indica (L) Gaertn.) plants of
three dinitroaniline-herbicide resistant (R) and three susceptible (S) biotypes from
North Carolina, South Carolina, and Mississippi was analyzed in greenhouse
experiments. Leaf area and biomass measurements, including root, shoot,
above-ground, and total dry weights were similar among the biotypes studied....
Field, screenhouse, and laboratory experiments were conducted to
study weed interference in rice grown on hydromorphic soils at the
International Institute of Tropical Agriculture (IITA) at Ibadan, Nigeria.
Rice and weeds emerged at the same time, 1 week after planting.
Weed dry weight was significantly reduced when the crop was...
The behavior of metribuzin [4-amino-6-(1,1-
dimethylethyl)-3-(methylthio)-1,2,4-triazin-5(4H)-one] and
ethyl-metribuzin (4-amino-6-(1,1-dimethylethyl)-3-
(ethylthio)-1,2,4-triazin-5(4H)-one] in soil was studied to
determine if differences in herbicide behavior in soil could
explain (a) the inconsistent herbicidal activity of these
chemicals and (b) the greater activity of metribuzin, as
compared to ethyl-metribuzin.
Metribuzin had higher activity than ethyl-metribuzin...
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...
Weedy rye (Secale spp.) is a weed in the winter-wheat- growing
regions in the Pacific Northwest and surrounding regions. Ethiazin
(4-amino-6-(1,1-dimethylethyl)-3- (ehtylthio)-1,2,4-triazine-5 (4H)-one)
has shown selective control of weedy rye in the cultivar 'Stephens',
(Triticum aestivum). Field, greenhouse, and outdoor pot experiments
were conducted to determine factors influencing selectivity.
Field...
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)...
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....
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...
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)...
Cyperus esculentus L. var. esculentus is a serious weed
problem in northwest Spain. Long-term control from glyphosate and
other herbicides has been inconsistent. Field, greenhouse, and
laboratory studies were conducted on factors influencing the
activity of glyphosate on C. esculentus.
In field studies, glyphosate controlled foliage growth at most
growth...
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....
Apoplastic distribution patterns of atrazine [2-chloro-4-(ethylamino)-
6-(isopropylamino)-s-triazine], glyphosate [N-(phosphonomethyl)-
glycine], the naturally occurring apoplastic leaf solutes, and
the apoplastic dye PTS (trisodium 3-hydroxy-5,8,10-pyrenetrisulfonate)
were compared. Aliquots of sap were expressed from intact
sunflower leaves in a pressure chamber over intervals of 0.2 to 0.4
bars. Three distinct fractions were detected...
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...
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...
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...
Equipment for strip-till planting is under development in wheat-fallow
rotations in the Columbia Basin of Oregon. This involves the
absence of tillage during the fallow season. At planting time, the
strip-till planter creates a narrow band into which the wheat seed is
placed. The area between the rows is undisturbed...
Paraquat (1,11-dimethy1-4,4'-bipyridinium ion) and glyphosate [N (phosphonomethyl)glycine] are herbicides utilized for chemical seedbed preparation in the establishment of grass and legume seed crops. When these herbicides are applied after seeding the crop, seeds which are not protected by a layer of soil could be exposed to the herbicide. Effects of...
Applications of ethofumesate in Oregon have been observed from
previous research and from commercial use to be less effective when
applied to dry soils, even if subsequent precipitation occurred
within a few days. Two field studies were established in the
summer of 1979 using sweet corn (Zea mays L. 'Jubilee')...
EPIC (S-ethyl dipropylthiocarbamate) is a selective herbicide
which controls some annual grasses, annual broadleaves, and perennial
grasses when incorporated into the soil before planting. In the last
few years, reports have been received of certain fields in the
Willamette Valley of Oregon in which EPIC was no longer effective.
Preliminary...
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...
Diclofop (2- [4 -(2, 4-dichlorophenoxy)phenoxy] propanoic
acid), formulated as the methyl ester, selectively kills
barnyardgrass [Echinochloa crus -galli (L.) Beauv.] in several
crops when applied postemergence. Studies were conducted
to determine the effect of soil moisture, barnyardgrass age, and site of exposure on control of barnyardgrass with diclofop. Soil moisture...
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...
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...
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...
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...
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...
Tansy ragwort (Senecio jacobaea L. ) is a poisonous weed which
infests alfalfa fields in western Oregon. Studies were conducted to
evaluate the effectiveness of asulam (methyl sulfanilylcarbamate)for
control of tansy ragwort in alfalfa and to elucidate factors responsible
for its selectivity. In seven replicated field trials in 1973 and...
In previous research in Europe, asulam (methyl sulfanilylcarbamate)
was found to be a potentially useful herbicide for controlling
broadleaf dock Rumex obtusifolius L. ) in permanent pastures.
Asulam was also reported to have a low margin of safety when used
on common pasture species. Field studies were conducted in western...
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...
Wheat is the major crop produced on the Anatolian Plateau of Turkey. Annual weeds cause large yields reductions in the wheat crop. Several formulations of 2, 4-D and mixtures of 2, 4-D and 2,4, 5-T are the only materials currently available for use in Turkey on wheat. The objective of...
A field study was conducted in 1973 and 1974 to determine optimum
timing of metribuzin (4-amino-6-tert-butyl-3(methylthio) as -
tria.zine-5(4H)one) on winter wheat (Triticum aestivum L. 'Hyslop')
for control of Italian ryegrass (Lolium multiflorum Lam. ). Herbicide
treatments were applied at 5 different stages of growth of winter wheat.
Metribuzin at...
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...
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...
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...