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1.
In field experiments methabenzthiazuron at 1.1 kg ai/ha applied pre-emergence gave good control of Poa trivialis L. in perennial ryegrass S23 which was undersown in spring barley (Zephyr); no significant damage to barley or perennial ryegrass resulted from 2.2 kg ai/ha. However this dose applied when barley had three to four leaves decreased the subsequent barley yield. In pot experiments in the glasshouse methabenzthiazuron was active mainly due to uptake through the soil. Much greater damage to barley and perennial ryegrass resulted when herbicide-treated soil was placed below seed level than above the seed. The difference was less marked with P. trivialis. The latter started to develop secondary roots near the soil surface earlier than either perennial ryegrass or spring barley. 相似文献
2.
Asulam was evaluated in three fields experiments for the control of Yorkshire fog (Holcus lanatus L.) in perennial rygrass(Lolium perenneL). It was used in 1976 on a 3 year-old ryegrass/timothy (Phleum pratense L.) sward in comparison with propyzamidc, in 1977 on a 9 year-old ryegrass pasture grazed at two stocking rates and in 1978 on an intensively managed ryegrass dominant sward. Asulam at 1.75 kg ha?1 gave good selective control in all the field experiments and was more effective under higher than lower slocking rates. In laxly grazed swards it was most effective when sprayed in October. Propyzamide also controlled H. lanatus and increased yields of while clover (Trifolium repens L.) even at 0.25 kg ha?1 but it damaged the sown grasses and increased the growth of broad-leaved weeds. 相似文献
3.
Two field experiments compared various sequences of ethofumesate, methabenzthiazuron and mecoprop, and mixtures of metamitron, ethofumesate and methabenzthiazuron for their control of Poa annua L. and Stelluria media (L). Vill. during the establishment of autumn-sown perennial ryegrass (Lolium perenne L.). In experiment 1 pre-emergence treatments required a second, post-emergence spraying to give complete control of P. annua. Grass seedlings reappeared in early spring following ethofumesate treatment, but populations built up earlier where methabenzthiazuron had been used. The most successful treatment was ethofumesate at 1.4 kg a.i. ha?1 followed by 0.7 kg a.i, ha?1 in spring. Methabenzthiazuron at 0.8 kg a.i. ha?1 followed by ethofumesate at 0.7 kg a.i. ha?1 in December was also effective. Methabenzthiazuron at 1.6 kg a.i. ha?1 damaged ryegrass but was effective as a secondary treatment at lower doses in spring. Most treatments controlled S. media satisfactorily, but this sometimes increased the yield of P. annua. Metamitron greatly reduced tiller numbers of P. annua in experiment 2, especially when sprayed with methabenzthiazuron. Only treatments which included ethofumesate controlled S. media adequately but there was no advantage in combining this herbicide with any other for controlling P. annua. 相似文献
4.
The competitive ability of Festuca rubra L., Hoicus lanatus L. and Poa trivialis L. when grown from seed, in monoculture and in 1:1 additive mixtures with Bromus sterilis L. was studied. B. sterilis was more aggressive when grown in additive mixtures with F. rubra than P. trivialis or H. lanatus. H. lanatus was less dominated by B. sterilis at the second harvest; visual observations suggested that this dichotomy was due to its slower initial growth rate, and its subsequent dense vegetative growth habit. There was no statistically significant difference between the Relative Yield Total (RYT) of B. sterilis in additive mixtures with F. rubra, H. lanatus or P. trivialis, indicating that they were competing for the same resources. B. sterilis produced significantly more reproductive tillers and seeds as a result of nitrogen application, and such production was accentuated in the absence of interspecific competition. The implications of sown grass strips for field margin management are discussed. 相似文献
5.
The effects of asulam applied in September 1970 at 0.55, 1.12 and 2.24 kg a.i./ha on Rumex obtusifolius (L.), Lolium perenne (L.), Other grasses and Trifolium repens (L.) growing in two swards in Wales were investigated. Good short-term control of Rumex was achieved by all rates of asulum although regeneration was occurring by the spring following treatment. Dry matter yields of L. perenne were slightly lowered by 2.24 kg a.i./ha 6 weeks after spraying but production in the spring following treatment was substantially greater than on untreated plots. Poa trivialis (L.) and Agrostis stolonifera (L.) were substantially reduced but invasion of the bare spaces by P. trivialis and P. annua (L.) seedlings tended to mask the success of this control. No harmful effects on T. repens were recorded. 相似文献
6.
A. K. OSWALD 《Weed Research》1980,20(5):305-309
The effects of dalapon applied in March and April at doses between 1·7 and 2·8 kg/ha a.e. on Poa trivialis present in crops of perennial ryegrass grown for seed, were investigated. Good control of P. trivialis was achieved at all doses sprayed at both times. Reductions in numbers of inflorescences and yield of seed of perennial ryegrass were however recorded, particularly after applications in March. Differences in the response of perennial ryegrass cultivars were also observed; cultivar S.23 was more susceptible to the herbicide than cultivar S.24. The results also suggest that the variation in response of cultivar S.24 in different experiments within the study may be due to the influence of climatic factors. Lutte sélective contre Poa trivialis avec le dalapon dans des cultures porte-graines de ray-grass vivace. Les effets du dalapon, appliqué en mars et en avril à des doses comprises entre 1,7 et 2,8 kg/ha (é.a.) sur Poa trivialis présent dans des cultures porte-graines de ray-grass vivace, ont étéétudiés. Une bonne efficacité sur Poa trivialis a été obtenue à toutes les doses appliquées aux deux époques. Toute fois, des réductions du nombre des inflorescences et des rendements en graines du ray-grass vivace, ont été constatés, particuliérement aprés les applications faites en mars. Des différences entre les réactions des cultivars ont été aussi observées: le cultivar S.23 s'est révélé plus sensible que le cultivar S.24. Les résultats suggèrent que les réactions différentes du cultivar S.24 dans diverses expériences comprises dans ce travail, peuvent également êre dues à l'influence de facteurs climatiques. Selektive Bekämpfung durch Dalapon von Poa trivialis in Deutschem Weidelgras für Samenproduktion Die Wirkung von Dalapon gegen Poa trivialis in Kulturen zur Samengewinnung von Deutschem Weidelgras wurde untersucht. Im März und April wurden Dosierungen zwischen 1,7 und 2,8 kg/ha appliziert. Poa trivialis konnte in alien Dosierungen und an beiden Behandlungszeitpunkten bekämpft werden. Minderungen in der Zahl der Blutenstände und Grassamenerträge von Deutschem Weidelgras wurden jedoeh festgestellt, insbesondere nach Applikation im März. Ebenfalls reagierten die Weidelgrassorten untersehiedlich. Sorte S.23 war gegen das Herbizid empfindlicher als Sorte S.24. Die Resultate deuten auch an, dass die unterschiedliche Reaktion von Sorte S.24 in den Experimenten dieser Untersuchung auf den Einfluss von Klimafaktoren zurückgeführt werden könnte. 相似文献
7.
D. HAWTON 《Weed Research》1980,20(1):33-40
In field experments on the Altherton Tableland. Queensland. Auslralia, methabenzthiazuron used at 1 2 kg ha pre-emergence was the most effective herbicide for selectively controlling Eleusine indica (L.) Gaertn in seed crops of Setaria anceps Stapf. Bromoxynil. bromoxynil plus MCPA, simazine and terbutryne were either ineffective or phytotoxic to S anceps. A more reliable technique was the use of diuron applied at 2.8 kg ha pre-emergence when the crop row was physically protected with metal shields at spraying or when activated carbon applied as a slurry in water at 168 kg per sprayed ha was sprayed in a 3 cm wide band over the crop row at sowing Three successive applications of paraquat over a 39 day period prior to sowing the crop were necessary for effective control of E. indica using the ‘stale seed bed’ technique 相似文献
8.
Akihiko Kamoshita Hiroyuki Ikeda Junko Yamagishi Bunna Lor Makara Ouk 《Weed Biology and Management》2016,16(3):93-107
The effects of the planting method (transplanting vs. direct seeding), rice cultivar (Sen Pidao vs. Phka Rumduol), and herbicide application (admixture of bentazone and cyhalofop‐butyl) on weeds and weed seed banks were quantified in unflooded, shallowly flooded, and deeply flooded paddy fields in Cambodia in 2005 and 2006. Broad‐leaved weeds infested more toward maturity in 2006 than in 2005, particularly in directly seeded plots. Weed dry weights at pre‐heading and/or maturity were consistently reduced by herbicide application and Phka Rumduol cultivar, while weed numbers increased under unflooded condition. The proportion of sedges was consistently larger in directly seeded and non‐herbicide plots at pre‐heading. Larger numbers and dry weights of sedges and total weeds in 2005 caused larger seed bank sizes of sedges and total weeds in 2006, which further caused their infestation in 2006. A greater weed dry weight at 62 days after sowing in 2005 resulted in larger seed banks of Cyperus iria and Fimbristylis miliacea, which were most severe under non‐herbicide, direct‐seeded treatment, while that at rice maturity resulted in larger seed banks of Cyperus difformis, Scirpus juncoides, and Lindernia antipoda. Overall, sedges shared the majority of the total weed seed bank, followed by broad‐leaved weeds and then grasses. A lower yield in 2005 led to significantly larger seed bank sizes of sedges, but not of grasses or broad‐leaved weeds. Rice yield reduction was consistently related to larger numbers of sedges by heading and those of grasses at maturity. 相似文献
9.
A cultivar of Lolium perenne L. (Causeway) selected for tolerance to foliar-applied paraquat was shown also to be tolerant at seed germination and establishment. When seeds were germinated in paraquat solutions (1, 3, 9, 27 ppm), Causeway was more than ten times as tolerant as a normal cultivar of L. perenne. When germination and survival were studied in a soil which had been sprayed with paraquat (0.0, 0.3, 0.9, 2.7 kg/ha) before sowing, Causeway was nearly three times as tolerant as a normal cultivar. Holcus lanatus L. was about equal to normal L. perenne, but Poa trivialis L. was less tolerant. Phytotoxicity was greater in a 10.5% organic than a 4.8% organic soil. It is concluded that the mechanism of paraquat tolerance operates in the non-photosynthetic tissues of germinating seedlings as well as in the photosynthetic tissues of older plants, although the degree of tolerance varies according to the mode and stage of application of the herbicide. There might be advantages in using a paraquat tolerant cultivar of L. perenne when direct drilling grass after sward destruction by paraquat. 相似文献
10.
J. M. GARCIA-BAUDIN A. R. LANSAC L. AYERBE† J. L. TENORIO† E. CADAHIA 《Weed Research》1985,25(5):319-322
Some substituted urea herbicides (chlortoluron, diuron and methabenzthiazuron) were tested for possible use in the cultivation of Euphorbia lathyris L. Diuron showed high phytotoxicity for this species, which was tolerant to chlortoluron and methabenzthiazuron. In preliminary experiments two triazine herbicide (atrazine and simazine) were also used, but both were so toxic to E. lathyris that their use was not continued beyond this stage. In glasshouse experiments, chlortoluron showed slight phytotoxicity to E. lathyris but this did not appear in field experiments. Both chlortoluron and methabenzthiazuron were very efficient against weeds which were present and significantly increased yield of E. lathyris in comparison with unweeded plots. The poor competitive ability of E. lathyris against weeds was confirmed. 相似文献
11.
D. J. TURNER 《Weed Research》1985,25(4):289-299
In pot experiments, mixtures of ammonium sulphate with surfactants or oil additives increased the phytotoxicity of commercially formulated bentazone (‘Basagran’) to Stellaria media (chickweed). Ammonium sulphate with a proprietary oil adjuvant Actipron had similar effects with benazolin potassium salt, but not with an ethyl ester formulation of benazolin. The phytotoxicity of bentazone and benazolin salts to Trifolium repens (white clover) and Lolium perenne (perennial ryegrass) was almost unaffected by these additives. In a field experiment, a mixture of ammonium sulphate with Actipron improved the control of S. media by bentazone and benazolin salts. Oils and surfactants markedly increased rates of entry of 14C bentazone into leaves of S. media, white clover and Chrysanthemum segetum. Ammonium sulphate sometimes had similar effects but on other occasions reduced uptake. In some circumstances the additives apparently interacted synergistically, to increase uptake of labelled herbicide into the leaf or to enhance its transport within the plant. In these test species, differential absorption of bentazone could not explain differences in species susceptibility, suggesting that the main cause of resistance was the ability of plants to degrade the herbicide. 相似文献
12.
V. N. Saraswat 《国际虫害防治杂志》2013,59(3):391-398
Abstract Sodium 2,2,3,3-tetrafluoropropionate (TFP) was tested as pre-planting and post-emergence applications on jute heavily infested with grasses and sedges. The herbicide was applied by two methods, at several rates and at different times before sowing. As a post-emergence application it was sprayed over a three week old crop. The best results were obtained when the herbicide was incorporated into the soil ten days before sowing at 3–4 kg a.i./ha. This practice controlled all grasses and sedges except nutsedge, which was only reduced by 30–40%, although higher rates gave better control. No phytotoxic effects on jute were observed with this rate and method of application. 相似文献
13.
Abstract A field experiment was conducted for two years during 1977–78 and 1978–79 to evaluate the efficiency of methabenzthiazuron, terbutryn and metoxuron in controlling weeds in peas (Pisum sativum) at the Punjab Agricultural University, Ludhiana, India. Pre-emergence application of methabenzthiazuron at 1.05 and 1.40 kg a.i./ha gave efficient weed control and gave comparable yields to two hand hoeings. Post-emergence application of methabenzthiazuron proved inferior. Terbutryn pre-emergence showed promise but as a post-emergence application it was ineffective. Metoxuron both pre- and post-emergence showed phytotoxic effects on the crop. 相似文献
14.
A. R. Saghir 《国际虫害防治杂志》2013,59(3):282-285
Abstract Wheat and barley constitute the bulk of agricultural production in the Middle East. Unfortunately, these crops are grown on marginal soils which are infested with annual and perennial weeds. The principal weed species include Avena sterilis L., Convolvulus arvensis L., and Sinapis arvensis L. and it has been estimated that yield losses due to weeds are between 20 and 30%. Control is mostly by hand pulling, hoeing or mechanical tillage, the use of herbicides being limited to about 2–5%, of the cereal area. The chemical used is usually 2,4-D but there are a few applications of barban. With the increase in wages, and unavailability of agricultural labour it is suggested that herbicide application should be widely used in the Middle East. Mixtures with benzonitriles and dicamba should be used in addition to the economical phenoxy herbicides to widen the spectrum of control of broadleaved weeds. Glyphosate may also be used after grain harvest for the control of perennial weeds and tri-allate, chlortoluron and other chemicals for the control of wild oats and other grasses. Plant breeders should study the genetic response of newly developed varieties to the most widely used herbicides. 相似文献
15.
Two potential control methods for Elymus repens, which do not disturb the soil, are post‐harvest mowing and competition from under‐sown cover crops. Our aim was to quantify the effect of cover crop competition and mowing on E. repens and to evaluate the potential for combining the two methods. We present a two‐factorial split‐plot experiment conducted at three locations in Sweden, in two experimental rounds conducted in 2011–2012 and 2012–2013. A spring cereal crop was under‐sown with perennial ryegrass, red clover or a mixture of the two (subplots). Under‐sown crops were either not mowed, or mowed once or twice post‐harvest (main plots). This was followed by ploughing and a new spring cereal crop the next year. Mowing twice reduced autumn shoot biomass by up to 66% for E. repens and 50% for cover crops compared with the control, twice as much as mowing once. Pure ryegrass and mixture treatments reduced E. repens shoot biomass by up to 40% compared with the control. Mowing twice reduced rhizome biomass in the subsequent year by 35% compared with the control, while the pure red clover treatment increased it by 20–30%. Mowing twice and treatments including red clover resulted in higher subsequent grain yields. We concluded that repeated mowing has the potential to control E. repens, but a low‐yielding cover crop has insufficient effect on rhizome biomass. Clover–grass mixtures are of interest as cover crops, because they have the potential to increase subsequent crop yield and even at low levels they reduce E. repens above‐ground autumn growth. 相似文献
16.
TRUDY A. WATT 《Weed Research》1983,23(5):267-271
The potential of the fungicide tridemorph selectively to control established plants of Holcus lanatus L. in ryegrass (Lolium perenne L) and Bromus sterilis L. in barley (Hordeum vulgare L.) was examined in glasshouse trails. A dose of 4.2 kg ha?1 tridemorph gave selectively between H. lanatus and ryegrass similar to, but more costly than, that which would be provided by 1.2 kg ha?1 asulam. B sterilis was more sensitive to tridemorph than was barley. Two additives, glycerol and the oil-surfactant mixture ‘PF’ enhanced this selectivity when tridemorph was applied at 2.1 kg ha?1. 相似文献
17.
Both uncontrolled weed growth and vegetation‐free orchard floors have been shown to affect coffee (Coflea arabica L.) negatively, but using cover crops as a solution has yielded conflicting results in different studies. In this study we tested the establishment success of three cover crop species under different management intensities and planting densities, as well as their long term weed‐controlling abilities and effects on weed community composition. Monthly manual weedings during the first 12 weeks after planting resulted in more rapid and extensive cover crop development compared with less intensive management. Transplanted Commelina diffusa Burm. f. grew most rapidly and controlled weeds by limiting light availability, but disappeared during the dry season and failed to establish at all on one of the farms. Arachis pintoi established and persisted for over 2 years, providing excellent weed control by outcompeting weeds for water and/or nutrient resources. Desmodium ovalifolium Wall required the longest time to establish and controlled weeds by an undetermined competitive mechanism. The sowing method of Desmodium led to intense intraspecific competition which probably decreased its effectiveness. Both Arachis and Desmodium led to lower relative abundances of grassy weeds and more perennial forbs, but total weed biomass was so low that these differences have no practical implications. 相似文献
18.
R. J. Wood 《国际虫害防治杂志》2013,59(1):86-88
Abstract Treating maize seed and cowpea seed with activated carbon or naphthalic anhydride permitted highly selective and economic early control of grasses and some broadleaved weeds with respectively EPTC and linuron and EPTC and chloramben. Without protectant every herbicide treatment produced less crop yield than with protectant. Early season control of grasses with herbicides followed by one row-cultivation controlled weeds throughout the crop. 相似文献
19.
Estimation of thresholds for weed control in Australian cereals 总被引：1，自引：0，他引：1
A non-linear model relating crop yield to the density of weeds was fitted to nine Victorian weeds to evaluate their competitive abilities. The weeds were: Acroptilon repens (L.) DC. (creeping knapweed), Chondrilla juncea L. (Skeleton weed, Raphanus raphanistrum L. (Wild radish), lolium rigidum Gaud. (Annual ryegrass), Lithospermum arvense L. (White iron weed), Brassica tournefortii Gouan (Wild turnip), Lamium amplexicaule L. (Deadnettle), Fumaria parviflora Lam. (White fumitory) and Amsinckia hispida (Ruiz & Pav.) I.M. Johnston (Amsinckia). Where more than one experiment was available for a weed, the net return for a herbicide treatment over a range of weed densities was calculated to obtain the economic threshold density. Generally, the economic threshold densities within a weed species were the same order of magnitude, except for the perennial Chondrilla Juncea L., For this species data were collected in years of contrasting rainfall. The model used here is discussed in view of the threshold approach currently used in continental Europe. 相似文献
20.
As herbicide‐resistant weeds have spread in the agricultural fields of grain‐exporting countries, their seeds could be introduced into other countries as contaminants in imported grain. The spread of resistance genes through seed and pollen can cause significant economic loss. In order to assess the extent of the problem, we investigated the contamination by herbicide‐resistant annual ryegrass (Lolium rigidum) of wheat imported from Western Australia into Japan. Annual ryegrass seeds were recovered from wheat shipments and seed bioassays were conducted to identify resistance to the herbicides that are commonly used in Australia: diclofop‐methyl, sethoxydim, chlorsulfuron, and glyphosate. Nearly 4500 ryegrass seeds were detected in 20 kg of wheat that was imported in both 2006 and 2007. About 35% and 15% of the seeds were resistant to diclofop‐methyl, 5% and 6% were resistant to sethoxydim, and 56% and 60% were resistant to chlorsulfuron in 2006 and 2007, respectively. None was resistant to glyphosate in either year. As the contamination of crops by herbicide‐resistant weeds is probably a common phenomenon, the monitoring of incoming grain shipments is necessary to stem the further spread of herbicide‐resistant weeds into importing countries. 相似文献