BENAZOLIN FOR SELECTIVE WEED CONTROL IN WHEAT AND OILSEED CROPS

1971 ◽  
Vol 51 (5) ◽  
pp. 371-376 ◽  
Author(s):  
E. S. MOLBERG ◽  
M. A. ASHRAFF

In field tests conducted between 1963 and 1969, wheat, Triticum aestivum L., flax, Linum usitatissimum L., Argentine rape, B. assica napus L., and Polish rape, B. campestris L., were tolerant to benazolin (4-chloro-2-oxo-3-benzothiazolineacetic acid). Wild mustard, Sinapia arvensis L., and redroot pigweed, Amaranthus retroflexus L., were controlled. Control of other weeds encountered in these tests was usually unsatisfactory. There was sufficient difference in tolerance of wild mustard and both species of rape to make selective control possible. In years when growing conditions were favorable, benazolin gave good control of wild mustard in rape at 0.56 kg/ha. When crop stands were poor due to dry, unfavorable weather a rate of 0.84 kg/ha was required. This sometimes caused light but visible injury to the rape, although crop yields were not significantly reduced. The selective properties of benazolin may make it possible to grow rape on land infested with wild mustard.

1996 ◽  
Vol 76 (4) ◽  
pp. 735-745 ◽  
Author(s):  
F. C. Stevenson ◽  
C. van Kessel

The inclusion of a pulse crop in a rotation often leads to greater seed yields in the succeeding cereal crop. Two rotations were established at three sites in 1993 to examine the N and non-N rotation benefits of pea (Pisum sativum L.) to the subsequent wheat (Triticum aestivum L.) then oilseed crops. Wheat seed yield was 43% greater (rotation benefit) when preceded by pea rather than wheat, a consistent response among sites. Six to fourteen kg ha−1 of the extra 27 kg ha−1 of N accumulated by wheat in the pea–wheat rotation was derived from the additional N derived from pea residue. The additional soil N availability in the pea–wheat rotation, as indicated by the A-value, explained 8% of the rotation effect on seed yield (N benefit). The remaining 92% of the yield advantage in the pea–wheat rotation was attributed to non-N rotation benefit. The yield of the oilseed crop following the pea–wheat phase of the rotation did not differ from that following the wheat–wheat phase. The influence of growing conditions and cropping history on the magnitude of the N to non-N rotation benefits, and the contribution of different non-N effects, should be investigated further. Key words: Rotation benefit, pea, wheat, residue N, non-N benefit


1979 ◽  
Vol 59 (2) ◽  
pp. 351-356 ◽  
Author(s):  
J. R. MOYER ◽  
R. D. DRYDEN ◽  
P. N. P. CHOW

Postemergent sprays of barban (4-chloro-2-butynyl m chlorocarbanilate) at the 2-leaf stage of wild oats (Avena fatua L.) and flamprop methyl [methyl N-benzoyl-N-(3-chloro-4-fluorophenyl)-2-aminopropionate] at the 3-leaf stage in water or solution nitrogen fertilizer gave moderate to good control of wild oats and significant increases of 21 and 30%, respectively, in yields of wheat (Triticum aestivum L. ’Neepawa’). Barban and flamprop methyl had no apparent effect on nitrogen content of wheat grain. When wild oats were controlled with herbicides the decrease in plant competition permitted increased growth of green foxtail (Setaria viridis L. Beauv.). Solution nitrogen and hand-weeding treatments increased nitrogen in the wheat grain significantly. Large increases in numbers and dry matter yields of wild oats resulted in relatively low crop yields from solution nitrogen, e.g. non-significant with barban and a 9% increase in the flamprop methyl experiment. Either herbicide applied with solution nitrogen produced an initial injury to plant leaves. However, wheat recovered rapidly and there was no indication of reduced growth at harvest. No effect was observed when herbicides were applied separately from solution nitrogen.


1977 ◽  
Vol 57 (3) ◽  
pp. 969-976
Author(s):  
P. N. P. CHOW ◽  
D. G. DORRELL

The role of TCA (trichloroacetic acid) in green foxtail (Setaria viridis (L.) Beauv.) control and its effect on seed yield and oil composition of flax (Linum usitatissimum L.) cvs. Noralta, Raja, and Redwood were re-assessed under various weedy conditions from 1972 to 1975. When a mixture of weeds was present, TCA at 2.24 kg/ha controlled green foxtail but failed to control lamb’s-quarters (Chenopodium album L.) and redroot pigweed (Amaranthus retroflexus L.). However, TCA mixtures which included one or two broad-leaf herbicides gave good control of all weeds and a 40% increase in yield over the untreated check. Under natural infestation conditions where green foxtail was light but the predominant weed, TCA at 2.24–4.48 kg/ha gave partial weed control but did not increase the seed yield of flax. Cultivation consistently produced the highest yields and TCA alone generally produced the lowest yields. While the lower yields experienced with TCA were partially offset by cultivating before or after the application of TCA, in no cases were the yields from these combined treatments ever equal to that of cultivation alone. Plants treated with 3.36 and 4.48 kg/ha of TCA in the greenhouse showed leaf injury and a significant reduction in top weight. It is suggested that this type of injury is one of the factors contributing to the failure of TCA to significantly increase the yield of flax following suppression of green foxtail growth. TCA tended to increase protein content but has little effect on oil content, fatty acid composition, or iodine number.


1987 ◽  
Vol 67 (4) ◽  
pp. 983-995 ◽  
Author(s):  
C. L. VERA ◽  
D. I. McGREGOR ◽  
R. K. DOWNEY

Variable amounts (up to 1.04 t dry wt ha−1) of herbage from seedlings of cultivars from four Brassica species (B. campestris L., B. napus L., B. hirta Moench and B. juncea (L.) Coss.) and straw and chaff (5 t ha−1) of B. campestris were incorporated into field plots to investigate the effect on subsequent stand establishment and seed yield of barley (Hordeum vulgare L.), oats (Avena sativa L.), wheat (Triticum aestivum L.), flax (Linum usitatissimum L.) and rapeseed (B. campestris). The amounts of plant material incorporated were considered representative of straw and chaff which might be deposited at harvest, or herbage which could originate from postharvest volunteer germination. Brassica herbage reduced stand establishment and seed yield of the oilseeds to a greater extent (65 and 53%, respectively) than that of the cereals (17 and 23%, respectively). Among the cereals, barley was the most affected, while oats did not show significant reductions of stand or yield. Generally the type of Brassica used to produce herbage did not influence the reduction of stand establishment or seed yield. Incorporation of straw and chaff of rapeseed in some instances resulted in reduced plant stands but did not show deleterious effects on seed yield, and in one case resulted in an increase in yield. For comparison, the effect of incorporating barley herbage on stand establishment and seed yield of barley and flax was also investigated. Incorporation of barley herbage also resulted in reduction of stand establishment (21%) and seed yield (26%) of subsequent crops, although its effect on stand establishment was less pronounced than for Brassica herbage (44%). It is recommended that a cereal, in particular oats, follow rapeseed or mustard in the crop rotation in order to avoid losses from deleterious effects.Key words: Brassica campestris, Brassica napus, Brassica juncea, Brassica hirta, rapeseed, mustard, crop residue, phytotoxicity


1991 ◽  
Vol 71 (3) ◽  
pp. 831-839 ◽  
Author(s):  
A. G. Thomas

Annual surveys for weeds of fields seeded to spring wheat, barley, oats, flax, and canola in Manitoba were conducted during 1978, 1979, and 1981. Fields were surveyed during July and early August each year using a stratified random sampling procedure. Data for the crops and years were combined for analysis. The frequency, the area infested, and the density of the infestation were determined for each species. These three measures of the abundance of the weed were combined into a single synthetic value called relative abundance. Nine of the 152 species recorded by the surveyors accounted for 77% of the total relative abundance. Ranked in order by relative abundance, these species were green foxtail (Setaria viridis (L.) Beauv.), wild oats (Avena fatua L.), wild buckwheat (Polygonum convolvulus L.), annual smartweed (Polygonum spp.), Canada thistle (Cirsium arvense (L.) Scop.), lamb's-quarters (Chenopodium album L.), wild mustard (Sinapis arvensis L.), perennial sow-thistle (Sonchus arvensis L.), and redroot pigweed (Amaranthus retroflexus L.). Green foxtail was the predominant weed with an abundance value three times larger than wild oats or wild buckwheat. The pattern of dominance found in Manitoba fields was similar to results from comparable surveys in Saskatchewan and North Dakota. Key words: Relative abundance, weed survey, weed density, green foxtail, wild oats, wild buckwheat


2017 ◽  
Vol 5 (1) ◽  
pp. 123-129 ◽  
Author(s):  
Sumita Nag ◽  
Jiban Mitra

Flax (Linum usitatissimum L.), stoods in position third, being the largest natural fibre crop and simultaneously one of the five preeminent oilseed crops in the world. SSR/microsatellite markers are extensively utilized for genetic diversity analysis and cultivar identification considering their myriad abundance, co-dominant inheritance, steep polymorphism, reproducibility, and comfort of assay by PCR. Ten microsatellites were amplified in 27 genotypes of Flax. The study was undertaken to assess the genetic diversity in flax and to select most diverse genotypes for future breeding program. Primer efficiency parameters were studied. The 10 SSR loci amplified a total of 41 alleles that were used for genetic analysis. Most primers have PIC value greater than 0.5 and the LU6 marker was highly polymorphic PIC = 0.95. Estimates of RP̅ were highest for the primer LU1 (0.68). The maximum MI was observed for the primer LU10 (3.56). The H and D ranged from 0.26 to 1.78 and 0.36 to 5.40, respectively. According to Spearman rank correlation, PIC and MI were most important parameters in assessing the efficiency of whole set of 10 SSR primers. Dendrogram was constructed using the genetic similarity coefficients using UPGMA. PCo-A was also performed in support. Genetic diversity in Flax was revealed at molecular level.


1957 ◽  
Vol 37 (1) ◽  
pp. 69-83 ◽  
Author(s):  
H. A. Friesen ◽  
D. R. Walker

Oats, flax and barley were sprayed with various formulations of MCP (2-methyl-4-chlorophenoxyacetic acid) and 2,4-D (2,4-dichlorophenoxyacetic acid) at a number of Experimental Farms in Western Canada in 1954 and 1955. Each formulation was applied at 4 and 8 ounces of acid equivalent per acre at each of two dates, viz., Date 1, when the weeds were in the seedling stage less than 3 inches in height; and Date 2, at a stage coinciding with the first appearance of buds on the major weed species.Stinkweed (Thlaspi arvense, L.), wild mustard (Brassica kaber (DC.) L.C. Wheeler var. pinnatifida (Stokes) L.C. Wheeler), lamb's quarters (Chenopodium album L.), Russian pigweed (Axyris amarantoides L.), and ball mustard (Neslia paniculata L.), were effectively controlled by each of the MCP and 2,4-D formulations used. Russian thistle (Salsola kali L.), and red-root pigweed (Amaranthus retroflexus L.), were not satisfactorily controlled by MCP, whereas hemp nettle (Galeopsis tetrahit L.) was not controlled by 2,4-D. Wild buckwheat (Polygonum convolvulus L.) was not controlled by any of the treatments. Each treatment was more effective when applied during the seedling stage of the weeds.On the basis of wood control and yield of grain the results of this study favour the use of MCP over 2,4-D with either oats or flax. Oats was significantly more tolerant to MCP, particularly if treated during the early growth stages when weed competition was most critical. With flax, the difference in tolerance was most pronounced in favour of MCP at the later date of treatment. The 2,4-D ester and low volatile ester resulted in a preponderance of plant deformities, lowered the yields of both oats and flax and delayed the maturity of flax significantly. Barley yields in this study were not adversely affected by any of the treatments.


2000 ◽  
Vol 80 (4) ◽  
pp. 963-972 ◽  
Author(s):  
R. C. Van Acker ◽  
A. G. Thomas ◽  
J. Y. Leeson ◽  
S. Z. Knezevic ◽  
B. L. Frick

In 1997, a weed survey was conducted during July and August in fields of wheat, barley, oat, canola and flax in Manitoba. Field selection was based on a stratified-random sampling methodology using ecodistricts as strata. Species in the Poaceae family were most commonly observed in the survey, followed by species in the Polygonaceae, Asteraceae and Brassicaceae families. The six most abundant weed species were green foxtail [Setaria viridis (L.) Beauv.], wild oats (Avena fatua L.), wild buckwheat (Polygonum convolvulus L.), Canada thistle (Cirsium arvense L.), redroot pigweed (Amaranthus retroflexus L.) and wild mustard (Sinapis arvensis L.). The survey highlighted significant differences between ecoregions and between crops in residual weed infestations. The weed community in the Boreal Transition ecoregion was dominated by seven species, whereas fields in the Aspen Parkland and Lake Manitoba Plain ecoregions were dominated by two species and the Interlake Plain ecoregion was dominated by only one species. Although significant differences were found between the weed communities in crops, they were not as great as differences between ecoregions. The Manitoba residual weed community in 1997 was very similar to that reported for 1978–1981 and 1986, suggesting that the same species should remain a focus for weed management. Key words: Weed survey, weed relative abundance, weed distributions, Manitoba ecoregions


Weed Science ◽  
1981 ◽  
Vol 29 (3) ◽  
pp. 349-355 ◽  
Author(s):  
Richard Behrens ◽  
M. A. Elakkad

To study rainfall effects, simulated rainfall was applied to velvetleaf (Abutilon theophrastiMedic.), common lambsquarters (Chenopodium albumL.), wild mustard [Brassica kaber(DC.) L. C. Wheeler var.pinnatifida(Stokes) L. C. Wheeler], soybean [Glycine max(L.) Merr. ‘Hodgson’], and redroot pigweed (Amaranthus retroflexusL.) in greenhouse and field studies following foliar applications of the alkanolamine (AKA) salt or the butoxyethanol (BE) ester of 2,4-D [(2,4-dichlorophenoxy)acetic acid] at rates that induced equivalent levels of phytotoxicity. Simulated rainfall less than 1 min after herbicide treatment reduced the phytotoxicity of the AKA salt of 2,4-D to a much greater extent than that of the BE ester with effects ranging from elimination of all injury from the AKA salt to soybeans to no reduction in phytotoxicity of the BE ester to common lambsquarters. The quantity of simulated rainfall required to induce maximum reductions in phytotoxicity of the BE ester ranged from 1 mm on common lambsquarters to 15 mm on velvetleaf. The time interval from 2,4-D treatment until rainfall required to achieve a phytotoxic response level of 80% of that attained without rainfall varied greatly among plant species and herbicide formulations; ranging from less than 1 min for the BE ester on common lambsquarters to more than 24 h for the AKA salt on velvetleaf. The addition of an alkylarylpolyoxyethylene glycol surfactant to 2,4-D spray solutions reduced herbicide rates required to induce equivalent levels of phytotoxicity, increased losses in phytotoxicity of the BE ester caused by rainfall, and reduced the time interval from treatment to rainfall required to attain an equivalent level of phytotoxicity with the AKA salt.


Weed Science ◽  
1979 ◽  
Vol 27 (4) ◽  
pp. 401-415 ◽  
Author(s):  
Robert N. Andersen ◽  
Willard L. Koukkari

In growth chamber studies, we measured the movement of cotyledons and leaves or leaflets in seedlings of nine weed species to determine: the magnitude of movement, whether movements followed a rhythmic pattern, and if rhythmic movements were endogenously controlled. Seedlings were always entrained under a 15-h light:9-h dark regime. Measurements were made at 3-h intervals for 3 to 4 days under four light regimes: alternating 15-h light:9-h dark; continuous light; one 15-h light:9-h dark span, followed by continuous light; and a 15-h light:9-h dark regime, in which the dark span was advanced 9 h (phase shift) when measurements were begun. No clearly defined pattern of leaf movement was found in wild mustard [Brassica kaber(DC.) L. C. Wheeler var.pinnatifida(Stokes) L. C. Wheeler]. Daily rhythmic leaf movements that did not appear to be endogenously controlled were found in redroot pigweed (Amaranthus retroflexusL.) and black nightshade (Solanum nigrumL.). Circadian rhythmic leaf movements that appeared to be under endogenous control were found in jimson-weed (Datura stramoniumL.), common lambsquarters (Chenopodium albumL.), common cocklebur (Xanthium pensylvanicumWallr.), prickly sida (Sida spinosaL.), sicklepod (Cassia obtusifoliaL.), and coffee senna (Cassia occidentalisL.).


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