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1.
The survival of Alopecurus myosuroides Huds. seeds in soil   总被引:1,自引:1,他引:0  
S. R. MOSS 《Weed Research》1985,25(3):201-211
The survival of Alopecurus myosuroides seeds was studied in soil under arable cropping and short term grass leys in which seed return was prevented. At two winter wheat sites, where weed seeds were sown, the mean annual seed decline was 73–83% over a 2- or 3-year period. The rate of decline was similar with all the cultivation systems studied: ploughing, tine cultivation and direct drilling. Seeds buried initially by ploughing, and then not disturbed by cultivation, were slightly more persistent. At five arable sites with natural populations of A. myosuroides, seed numbers declined to an average of 3% of the original amount present after 3 years, and to 1% after 4 years. Initial populations of over 50 000 seeds m?2 were recorded. Plant populations were not always proportional to the total seed content of the soil, especially on ploughed land. Seed decline in two grass fields was similar to that under arable cropping. A. myosuroides plants were recorded in a wheat crop following a 2-year grass ley. Weed plants did not persist in the vegetative state in grass used for conservation and grazing. At all sites, appreciable quantities of seeds were still present in the soil after 2–4 years. Although a relatively small proportion of seeds survived, the actual number of seeds surviving was substantial. For this reason, it was concluded that any eradication policy is unlikely to be effective in a cropping system dominated by winter cereals.  相似文献   

2.
The distribution of Alopecurus myosuroides (black‐grass) in fields is patchy. The locations of these patches can be influenced by the environment. This presents an opportunity for precision management through patch spraying. We surveyed five fields on various types of soil using a nested sampling design and recorded both A. myosuroides seedlings in autumn and seed heads in summer. We also measured soil properties at those sampling locations. We found that the patches of seed heads within a field were smaller than the seedling patches, suggesting that techniques for patch spraying based on maps of heads in the previous season could be inherently risky. We also found that the location of A. myosuroides patches within fields can be predicted through their relationship with environmental properties and that these relations are consistent across fields on different soil types. This improved understanding of the relations between soil properties and A. myosuroides seedlings could allow farmers to use pre‐existing or suitably supplemented soil maps already in use for the precision application of fertilisers as a starting point in the creation of herbicide application maps.  相似文献   

3.
A survey of grass weeds in cereals in nine areas of central southern England was made in summer 1981 with the primary purpose of determining the importance of Bromus sterilis. A total of 1477 fields of winter wheat, 715 of winter barley and 434 of spring barley were assessed by visually scoring the whole field for grass flower heads. In all, 19 species were found; their levels of infestation were scored. In winter cereals the most frequent species were Avena spp. in 32% of fields. Agropyron repens in 24%, Poa trivialis in 22% and Alopecurus myosuroides in 19%. Bromas sterilis was next most frequent in 9%. In spring barley the two most frequent species were Agropyron repens in 53% of the fields and Avena spp. in 52%. The third most frequent was Alopecurus myosuroides in 1 1%. Bromus sterilis was recorded in 12% of winter wheat and 4% of winter barley crops, but did not occur in spring barley. Of the 206 fields where it was present it occurred throughout the field in only 82 and it was confined to the headlands in the remainder.  相似文献   

4.
The 1995/6 International Survey of Herbicide-Resistant Weeds recorded 183 herbicide-resistant weed biotypes (124 different species) in 42 countries. The increase in the number of new herbicide-resistant weeds has remained relatively constant since 1978, at an average of nine new cases per year worldwide. Whilst 61 weed species have evolved resistance to triazine herbicides, this figure now only accounts for one-third of all documented herbicide-resistant biotypes. Triazine-resistant weeds have been controlled successfully in many countries by the use of alternative herbicides. Due to the economic importance of ALS and ACCase inhibitor herbicides worldwide, and the ease with which weeds have evolved resistance to them, it is likely that ALS and ACCase inhibitor-resistant weeds will present farmers with greater problems in the next five years than triazine-resistant weeds have caused in the past 25 years. Thirty-three weed species have evolved resistance to ALS-inhibitor herbicides in 11 countries. ALS-inhibitor-resistant weeds are most problematic in cereal, corn/soybean and rice production. Thirteen weed species have evolved resistance to ACCase inhibitors, also in 11 countries. ACCase inhibitor resistance in Lolium and Avena spp. threatens cereal production in Australia, Canada, Chile, France, South Africa, Spain, the United Kingdom and the USA. Fourteen weed species have evolved resistance to urea herbicides. Isoproturon-resistant Phalaris minor infesting wheat fields in North West India and chlorotoluron-resistant Alopecurus myosuroides in Europe are of significant economic importance. Although 27 weed species have evolved resistance to bipyridilium herbicides, and 14 weed species have evolved resistance to synthetic auxins, the area infested and the availability of alternative herbicides have kept their impact minimal. The lack of alternative herbicides to control weeds with multiple herbicide resistance, such as Lolium rigidum and Alopecurus myosuroides, makes these the most challenging resistance problems. The recent discovery of glyphosate-resistant Lolium rigidum in Australia is a timely reminder that sound herbicide-resistant management strategies will remain important after the widespread adoption of glyphosate-resistant crops. ©1997 SCI  相似文献   

5.
A survey of grass weeds of cereals in central southern England made in 1981 was repeated in 1982 between 28 June and 23 July. Dicotyledonous weeds were also assessed in 1982. A total of 1021 fields were surveyed, 702 in winter wheat. 198 in winter barley and 121 in spring barley. A total of twenty-four grass weeds were found and their levels of infestation were scored. The most frequently found grass weeds were the same as in 1981. In all cereals combined, these were Elymus (Agropyron) repens in 35% of fields, Avena fatua in 32%, Alopecurus myosuroides in 26% and Poa trivialis in 24%. Sixty-three species of dicotyledonous weeds were recorded and of these, eighteen species occurred in 2% or more of fields. The eight most frequent were Viola arvensis, Galium aparine, Stellaria media, Myosotis arvensis, Polygonum aviculare, Convolvulus arvensis, Bilderdykia (Polygonum) convolvulus and Lamium purpureum. Most species were fairly uniform in distribution, but Galium aparine, Convolvulus arvensis and Cirsium arvense were most frequent in the east while Viola arvensis was least frequent there. The cereals varied in weediness, 32% of winter barley, 23% of spring barley and only 7% of winter wheat fields had no weeds recorded.  相似文献   

6.
Herbicide resistance in Alopecurus myosuroides causes severe problems in Western European cropping systems. Costs of herbicide resistance were investigated in this study by analysing variable production costs and sales revenues. Three farms were selected for this study, with winter wheat as the dominating crop in all farms. Resistance in A. myosuroides populations was verified at all locations. Four farming approaches were simulated over a period of 20 years: (i) continuing the actual cropping system without increase of resistance, (ii) continuing the actual cropping system with increase of resistance, (iii) changing cropping practice to overcome resistance and (iv) changing cropping practice to prevent resistance. Contribution margins representing the proportion of sales revenue that is not consumed by variable costs were calculated for all approaches. Comparative static simulations showed that average contribution margins in a cropping system with more than 60% winter cereals and reduced tillage practice dropped from 807 € ha?1 a?1 without herbicide resistance to 307 € ha?1 a?1 with herbicide resistance. Alopecurus myosuroides population densities increased to more than 1000 plants m?2. Diverse crop rotations, including spring crops, clover–grass leys and intensive tillage, suppressed A. myosuroides populations, and average contribution margin was 630 € ha?1 a?1. Preventive methods with rotations of winter cereals and spring crops with less clover–grass leys resulted in an average contribution margin of 691 € ha?1 a?1. In conclusion, rotations of winter cereals and spring crops combined with inversion tillage and herbicides provide stable yields and can prevent weed population increase.  相似文献   

7.
Herbicide‐resistant populations of Alopecurus myosuroides (black grass) have become widespread throughout the UK since the early 1980s. Previous observations in this laboratory have demonstrated that natural climatic fluctuations caused increases in endogenous glutathione S‐transferase (GST) enzyme activity in A. myosuroides plants as they mature, which is thought to be linked to herbicide resistance in this species. The present study has investigated the effects of plant growth at 10°C and 25°C, and reports GST specific activity and glutathione (GSH) pool size in resistant and susceptible A. myosuroides biotypes. Findings demonstrate differences in GST activity between resistant and susceptible populations, which are transient at lower growth temperatures. The GSH pool size was elevated at lower growth temperature in both biotypes. We speculate that these endogenous responses are part of a natural mechanism of acclimation to environmental change in this species and suggest that resistant plants are more able to adapt to environmental stress, as indicated in this instance by temperature change. These observations imply that the control of resistant A. myosuroides by graminicides may be more effective when applied at lower temperatures and at earlier growth stages.  相似文献   

8.
This study reviews 52 field experiments, mostly from the UK, studying the effects of cultivation techniques, sowing date, crop density and cultivar choice on Alopecurus myosuroides infestations in cereal crops. Where possible, a statistical meta‐analysis has been used to calculate average responses to the various cultural practices and to estimate their variability. In 25 experiments, mouldboard ploughing prior to sowing winter cereals reduced A. myosuroides populations by an average of 69%, compared with non‐inversion tillage. Delaying drilling from September to the end of October decreased weed plant densities by approximately 50%. Sowing wheat in spring achieved an 88% reduction in A. myosuroides plant densities compared with autumn sowing. Increasing winter wheat crop density above 100 plants m?2 had no effect on weed plant numbers, but reduced the number of heads m?2 by 15% for every additional increase in 100 crop plants, up to the highest density tested (350 wheat plants m?2). Choosing more competitive cultivars could decrease A. myosuroides heads m?2 by 22%. With all cultural practices, outcomes were highly variable and effects inconsistent. Farmers are more likely to adopt cultural measures and so reduce their reliance on herbicides, if there were better predictions of likely outcomes at the individual field level.  相似文献   

9.
We assessed the contributions of target site‐ and non‐target site‐based resistance to herbicides inhibiting acetyl‐coenzyme A carboxylase (ACC) in Alopecurus myosuroides (black grass). A total of 243 A. myosuroides populations collected across France were analysed using herbicide sensitivity bioassay (24 300 seedlings analysed) and ACC genotyping (13 188 seedlings analysed). Seedlings resistant to at least one ACC‐inhibiting herbicide were detected in 99.2% of the populations. Mutant, resistant ACC allele(s) were detected in 56.8% of the populations. Among the five resistant ACC alleles known in A. myosuroides, alleles containing an isoleucine‐to‐leucine substitution at codon 1781 were predominant (59.5% of the plants containing resistant ACC alleles). Comparison of the results from herbicide sensitivity bioassays with genotyping indicated that more than 75% of the plants resistant to ACC‐inhibiting herbicides in France would be resistant via increased herbicide metabolism. Analysis of herbicide application records suggested that in 15.9% of the populations studied, metabolism‐based resistance to ACC‐inhibiting herbicides was mostly selected for by herbicides with other modes of action. Our study revealed the importance of non‐target site‐based resistance in A. myosuroides. Using herbicides with alternative modes of action to control populations resistant to ACC‐inhibiting herbicides, the recommended management approach, may thus be jeopardised by the widespread occurrence of metabolism‐based resistance mechanisms conferring broad‐spectrum cross‐resistance.  相似文献   

10.
B. MELANDER 《Weed Research》1995,35(3):157-166
The impact of drilling date on Apera spica-venti and Alopecurus myosuroides in winter cereals was investigated in field trials in 1991 and 1992. Two drilling dates were considered with an inter val of 14 to 16 days between dates. Generally, drilling date had an inconsistent effect on weed plant populations in spring, but seedling emerg ence of both species appeared to be delayed at the later drilling compared with the earlier date. This delay may partly explain the reduced com petitive ability of A. myosuroides in wheat in 1991 and 1992 and of A. spica-venti in wheat in 1991 at the later drilling date. The seed popula tion per plant of both species was lower at the later date in some instances, whereas in others drilling date had no effect. Reduced seed produc tion was mainly caused by a reduction of the number of inflorescences per plant. The poten tial of utilizing drilling dates as a cultural control measure against grass weeds is discussed.  相似文献   

11.
BACKGROUND: The increasing use of ACCase‐inhibiting herbicides has resulted in evolved resistance in key grass weeds infesting cereal cropping systems worldwide. Here, a thorough and systematic approach is proposed to elucidate the basis of resistance to three ACCase herbicides in a Lolium multiflorum Lam. (Italian rye grass) population from the United Kingdom (UK24). RESULTS: Resistance to sethoxydim and pinoxaden was always associated with a dominant D2078G (Alopecurus myosuroides Huds. equivalent) target‐site mutation in UK24. Conversely, whole‐plant herbicide assays on predetermined ACCase genotypes showed very high levels of resistance to diclofop‐methyl for all three wild DD2078 and mutant DG2078 and GG2078 ACCase genotypes from the mixed resistant population UK24. This indicates the presence of other diclofop‐methyl‐specific resistance mechanism(s) yet to be determined in this population. The D2078G mutation could be detected using an unambiguous DNA‐based dCAPS procedure that proved very transferable to A. myosuroides, Avena fatua L., Setaria viridis (L.) Beauv. and Phalaris minor Retz. CONCLUSION: This study provides further understanding of the molecular basis of resistance to ACCase inhibitor herbicides in a Lolium population and a widely applicable PCR‐based method for monitoring the D2078G target‐site resistance mutation in five major grass weed species. Copyright © 2010 Society of Chemical Industry  相似文献   

12.
The occurrence of Fusarium species in winter wheat in southern Belgium (Wallonia) and the deoxynivalenol content in 692 samples collected in commercial fields in the region’s main cereal growing area were investigated. The main Fusarium species associated with head blight in wheat were identified at levels that varied from year to year. Interactions between fungal species causing head blight in wheat were detected, most of them positive. The years 2007 and 2008 were very conducive to the disease and there was a strong correlation between mean annual deoxynivalenol content and number of days with a mean relative humidity above 80% over a period starting from 7 days before the mean flowering date and ending 16 days after this date. A two-stage approach, based on type of year (at risk or not) and agricultural practices during risk years has been developed to help cereal storage companies reduce the risk of mixing sound and deoxynivalenol-contaminated lots at harvest and to limit the number of analyses.  相似文献   

13.
节节麦等三种禾本科杂草对不同性状土壤的适应性   总被引:1,自引:0,他引:1  
为明确不同性状土壤对小麦田重要的禾本科杂草节节麦Aegilops tauschi、多花黑麦草Alopecurus myosuroides和大穗看麦娘Lolium multiflorum出苗及生长的影响,在盆栽条件下研究了3种禾本科杂草对采自山东省不同区域的24份不同性状土壤的适应性。结果表明,节节麦适应性最强,在所有供试土样中均能正常出苗和生长,出苗率在64.2%~80.8%之间;多花黑麦草也有很强的适应性,在供试24份土样中出苗基本正常,出苗率均在90.1%以上,但有2份土样影响其后期生长的株高、鲜重等生长指标;大穗看麦娘的适应性略差,有4份土样明显影响其出苗,出苗率在32.5%~50.8%之间,在其它20份土样中出苗率均为70.0%左右,有11份土壤影响其生长期株高、鲜重、穗数或结实量。土壤性状中pH是影响杂草出苗及生长的最主要因素,pH小于6.0的强酸土壤和pH大于8.0的强碱土壤均对杂草生长会产生一定影响,另外,黏性土壤质地和高盐分土壤也对杂草生长有影响,其它土壤性状如氮含量、磷含量、钾含量、有机质含量和土壤类型对这3种禾本科杂草出苗及生长无影响。  相似文献   

14.
A survey of 2000 farms in south-west Scotland revealed that 3.5% of the cereal area had been treated with pesticides for the control of leatherjackets (Tipula spp.) in 1975. A small area of recently established grass and some turnip fields were also treated. DDT and gamma-HCH were the most commonly used compounds with an estimated use respectively of 1863 and 376 kg of active ingredient. Pesticide usage in 1975 appeared to have been consistent with the generally low leatherjacket population in that year.  相似文献   

15.
Substitution of isoleucine by leucine at the equivalent of residue 1781 of acetyl CoA carboxylase (ACCase) in Alopecurus myosuroides (I1781L) has been shown to be a key point mutation conferring resistance to most aryloxypropionate and cyclohexanedione herbicides in Lolium spp., A. myosuroides, Avena fatua and Setaria viridis. This substitution results from changing an adenine residue to either thymine or cytosine at position 5341 in the ACCase coding sequence of A. myosuroides and at the homologous position in the other species. The I1781L mutation can be detected by allele‐specific amplification assays. These are, however, very dependent on the conservation of the nucleotide sequences flanking the causative single nucleotide polymorphism. Moreover, such assays cannot distinguish between homozygous and heterozygous individuals in a single polymerase chain reaction reaction. Here we present an alternative derived Cleaved Amplified Polymorphic Sequence (dCAPS) method to define I1781L status in the ACCase enzyme of four grass weeds. This dCAPS approach is simple, economical, highly transferable between species and can readily distinguish homozygous Leu/Leu 1781 and heterozygous Ile/Leu 1781 resistant individuals, providing the basis for accurate measures of the frequency of the dominant Leu allele in a given population.  相似文献   

16.
Weed populations were monitored for 4 years on two experiments designed to compare the effect of different primary tillage treatments on winter wheat (Triticum aestivum L.) cropping. Ploughing was compared with deep and shallow tine cultivation and with no tillage on both a clay loam and a silt loam over chalk. Soil-acting residual herbicides were used to control weeds, especially Alopecurus myosuroides Huds. and Avena fatua L. Dicotyledonous weeds were uncommon on the clay loam but on the silt loam, in a year when no residual herbicide was used, they were most numerous where the soil was disturbed most. In other years there was little difference in the number emerging. Six species were reduced in number by reduced cultivation or no tillage, whilst four species, including two grasses, were increased. At both sites, A. myosuroides was more numerous on direct drilled and tine cultivated plots than on ploughed. Herbicides gave good control on the silt loam but failed to control the weed on the clay loam. On the clay loam, A. fatua was most numerous on tine cultivated plots and a combination of herbicides and roguing produced a decline in the population.  相似文献   

17.
Mixed infestations of Alopecurus m yosuroides Huds. and broad-leaved weeds in winter cereals were controlled with a commercial formulation of ioxynil + bromoxynil + mecoprop. used in mixtures or as sequences with isoproturon or clofop-isobutyl. As well as controlling A. myosuroides the mixtures, applied in the autumn, gave good control of Veronica persica Poir., Galium aparine L. Lilhospermum arvense L. and Viola arvensis Murr. weeds which were resistant to isoproturon used alone. A. myosuroides had the major influence on crop yield in three experiments. High infestations of A. myosuroides reduced the broad-leaved weeds so that crop yields were only slightly improved when all the weeds were controlled compared with the control of A. myosuroides alone. In the remaining experiment. V. persica was very competitive with wheat; additional control of A. myosuroides improved yields considerably. Ioxynil + bromoxynil + mecoprop gave better final control of broad-leaved weeds when applied in the spring rather than the autumn but the sequence of a spring application following isoproturon or clofop-isobutyl in the autumn did not improve yields compared with the mixtures applied in the autumn. In all experiments, the highest yields were obtained from controlling both A. myosuroides and broad-leaved weeds in the autumn, provided that good control of A. myosuroides was obtained.  相似文献   

18.
Studies were made of isolates of Gaeumannomyces graminis (Sacc.) Arx & Olivier var. tritici J. Walker from different length crop sequences of wheat and barley following permanent grassland. Studies were done on the influence of cropping intensity of soils, natural and steam disinfested, on disease expression from added inoculum. Efforts were also made to detect interactions between isolates and soils from the same and different cropping sequences. Investigation of variability in the pathogen related to virulence and specificity as well as to saprophytic traits. In general, mean virulence of isolates increased up to the point where approximately peak disease levels occurred in the field, and diminished subsequently. Host specificity of isolates from a monospecies system was also pronounced at this point whereas it was not evident in the first 2 crops; it did not increase further after the 5th or 6th cereal of a single species. There was evidence of loss of competitive saprophytic ability in isolates from long sequences as against those from 1st, 2nd and 3rd crops after permanent pasture. A differential sensitivity response from Gliomastix murorum (Cda.) Hughes var. felina (Marsh) Hughes was observed with isolates from 1 to a 3 year sequence compared with isolates from sequences of 4 to 8 years. Isolates from a 1st to a 3rd crop restricted colony growth of G. murorum in culture whereas those from 4th to the 8th cereal were overgrown by this fungus. Isolates from the 1st cereal after grass darkened considerably with age, those from a 2nd less so and those from a 3rd successive crop remained almost totally hyaline; those from longer sequences darkened considerably but were very variable for this trait. The influence of soil from more intensively cropped cereal sequences, which was destroyed by steam disinfestation, was to depress disease levels from applied inoculum. This soil inhibitory effect set in between the first and 3rd cereal.  相似文献   

19.
Lolium rigidum is an extremely competitive and prevalent grass weed in cereal fields of Mediterranean areas. The proper timing of control measures is a prerequisite to maximising herbicide efficacy, in terms of both improved control and reduced herbicide inputs. The development of models to predict emergence flushes will contribute to this goal. Pooled cumulative emergence data obtained during three seasons from a cereal field were used to develop a Gompertz model. This explained relative seedling emergence from crop sowing onwards as a function of: (i) standard soil thermal time accumulation (TT) with a base temperature of 1.8°C and (ii) soil thermal time accumulation corrected for soil moisture (cTT). For the latter, no thermal time accumulation was computed for days in which the soil water balance within the upper 10‐cm soil layer indicated no water available for plants, because evapotranspiration was greater than rainfall plus the stored water remaining from the previous day. The model was validated with six datasets from four different sites and seasons. Compared with TT, the model based on cTT showed better performance in predicting L. rigidum emergence, particularly in predicting the end of emergence. Complemented with in‐field observations to minimise deviations, the model may be used as a predictive tool to better control this weed in dryland cereal fields of Mediterranean climate areas.  相似文献   

20.
Summary. A 2-year comparison of the development of Avena fatua L. and Sinapis arvensis L., with spring barley and of Alopecurus myosuroides Huds, with winter wheat gave the following results:
  • 1 Avena fatua emerged shortly before barley in both years. Development until tillering was somewhat slower than that of barley, but after tillering the growth of both species was about the same. The first seeds of A. fatua matured shortly before harvest.
  • 2 Growth of Sinapis arvensis was slower than that of barley during the- early stages, but after tillering was more rapid. Growth ceased more than 10 days before harvest.
  • 3 In 1962–63 Alopecurus myosuroides germinated mainly in spring, but in 1963–64 most germination occurred in autumn, so that early development was different in the two years. After tillering the development WAS much faster than that of wheat and at the flowering stage of A. myosuroides, the shoots were taller than those of wheat. Seed was ripened some time before harvest.
  • 4 A comparison of the development of A. myosuroides and Avena fatua alone and in competition with cereals revealed no marked influence of competition on the pattern of development, but competition did cause some reduction in shoot length and a marked reduction in weight of the two weed species.
Compétition entre plantes cultivées et mauvaises herbes. I. Développement absolu el développement retalif des céréales et de quelques espèces de mauvaises herbes  相似文献   

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