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...
Previous research has shown that specific carotenoid pigments
function through oxidation-reduction reactions to protect chlorophyll
from photooxidation in the presence of reduced nicotinamide adenine
dinucleotide phosphate (NADP). The hypothesis that diuron (3-(3, 4-
d chloropheny1)-1, 1-dimethylurea) initiates phytotoxicity by inhibition
of NADPH synthesis was examined. All experiments were conducted
in...
Previous research has shown that activated carbon is effective
in inactivating certain herbicides applied as a preemergence treatment.
Studies were conducted in the greenhouse to determine the
influence of various factors on the ability of activated carbon to
inactivate herbicides applied after carbon application. Field studies
were conducted to determine...
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...
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 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....
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...
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. )...
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...
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...
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...
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...
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...
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...
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....
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...
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...
Addition of the methylcarbamate compounds p-chlorophenyl
N-methylcarbamate (PPG-124) and 1-naphthyl N-methylcarbamate
(carbaryl) to various herbicides has resulted in reduced rates of
degradation. Carbaryl affects the degradation of certain herbicides
in both plants and soils while PPG-124 has only been demonstrated
to affect degradation in soils. Both these materials are effective...
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...
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...
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)...
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...
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....
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...
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...
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...
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...
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,...
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...
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...
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...
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...
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...
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)...
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...
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 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...
Trifluralin (a, a, a - trifluoro -2, 6 -dinitro-N, N-dipropyl-ptoluidine)
is effective in controlling downy brome (Bromus tectorum
L.) and wild oat (Avena fatua L.) but does not severely affect the
growth of wheat (Triticum aestivum L.). Studies were conducted
using germination chamber and greenhouse facilities to investigate
possible factors...
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...