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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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....
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')...
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...
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...