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...
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...
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...
Studies were initiated to determine the response of two common
groundsel biotypes (Senecio vulgaris L. ) to several s-triazine herbicides.
Herbicides tested were: 2-chloro-4,6-bis(ethylamino)-striazine
(simazine), 2-chloro-4-(ethylamino)-6-(isopropylamino)-
s-triazine (atrazine) 2-(sec-butylamino)-4-(ethylamino)-6-methoxys-
triazine (GS-14254), 2, 4-bis(isopropylamino)-6-methoxy-striazine
(prometone), 2-(tert-butylamino)-4-(ethylamino)-6-methylthio-
s-triazine (terbutryn), and 2, 4-bis(isopropylamino)-6-
methylthio-s-triazine (prometryne). One biotype was much more
susceptible than the...
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...
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...
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...
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...
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...
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...
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...
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...
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. )...
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...
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...
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...
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...
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...
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...
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...
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...
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...