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1.
The uptake and translocation of 14C-labelled ethofumesate [(±)-2-ethoxy-2,3-dihydro-3,3-dimethylbenzofuran-5-yl methanesulphonate] was studied in sugar-beet seedlings following soil and foliar applications. After soil applications, the roots absorbed and translocated to the foliage more ethofumesate or its metabolites than did the emerging hypocotyls. Ethofumesate or its metabolites did not accumulate in either roots or hypocotyls after exposure to treated soil. When sugar-beet leaves were treated with the herbicide at the two-leaf stage, acropetal translocation was rapid but there was no translocation out of the treated leaves. Furthermore, ethofumesate or its metabolites were not translocated basipetally after either soil or foliar application. 相似文献
2.
In four field experiments begun in 1963, each of four herbicides was applied to plots planted wilh the same crop each year. The annual treatments were: MCPA at 17 kg/ha to barley (Hordeum sativa Jess) and wheat (Triticum aestivum L.) at growth stage 15. tri-allate at 17 kg/ha pre-emergcnce to barley and wheat, simazine at l7kg/ha pre-emergence to maize (Zea mays L.) and linuron in two applications of 084 kg/ha pre- and post-emergence to carrots (Daucus carota L.). MCPA did not affect growth or yield of either barley or wheat. In general tri-allate also did not aftect the crops although wheat yield was depressed in 1978, wheat 1000 grain weight was reduced in 1972 and barley germination percentage was increased in 1973. Simazine did not influence the height, yield or appearance of maize. Linuron normally produced no effect on carrot yield, density and size. However, in 2 years when the post-emergence application was late, density but not yield was lower than in control plots. There was no accumulation of residues of any of these compounds in the soil. Rates of loss were similar to those predicted on ihe basis of laboratory experiments. In a fifth experiment these herbicides were applied twice per year (3 times in the case of linuron) at double the rales above on each occasion to bare plots. These applications ceased in 1968 (1969 for MCPA) but residues were monitored until 1972 except in the case of MCPA. Disappearance rates were similar to those in the cropped plots and residues were largely confined to the top 10 cm. The plots treated with MCPA had developed an enhanced ability lo degrade il prior to 1968. This persisted for 5 years after the final application. 相似文献
3.
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
4.
Field experiments at Lacombe on a Ponoka loam soil (9·6% organic matter) during 1982 and 1983 investigated the tolerance of spring wheat (Triticum aestivum L.) cv. Neepawa in a weed free situation to trifluralin applied at 0·0–3·0 kg ai ha?1 in the autumn or spring and incorporated to a depth of 10 cm. Rates of trifluralin above 1·0 kg ai ha?1 applied in the autumn or spring reduced the percent stand of wheat compared to an untreated control. Two weeks after emergence the crop showed 37 or 47% injury indicated by delayed growth, following application at 1·0 kg ai ha?1 in the autumn or spring, respectively. The wheat recovered throughout the course of the growing season. At harvest, trifluralin applied in the autumn or spring at rates below 1·0 kg ai ha?1 caused a yield increase while higher rates caused a yield decrease compared to the untreated control. Spring application caused a greater yield loss than autumn application. The tolerance of spring wheat to trifluralin at rates required for weed control (1·1 kg ai ha?1 or higher) on this soil type is marginal. 相似文献
5.
Summary. Spikes oi Agropyron repens (L.) Beauv. were collected from field crops (mostly spring barley and winter wheat) in England and Wales near the time of crop harvest. Seeds per spike were counted and their germination tested in soil in the glasshouse.
About 95% of the samples contained viable seeds; about one third of the samples had fewer than 5 viable seeds/spike, a third between 6 and 15 and a third more than 15. The average number of viable seeds/spike for all samples was 13. Spikes from spring barley (152 samples) had an average of 11 and a maximum of 51 viable seeds and those from winter wheat (42 samples), 20 and 48 respectively. Samples collected within 3 weeks after mid-July had fewer viable seeds/spike than those collected later. Samples containing morphologically-different spikes had more viable seeds/spike than apparently uniform samples, and spikes from dense field populations more seeds than those from sparse populations. 相似文献
About 95% of the samples contained viable seeds; about one third of the samples had fewer than 5 viable seeds/spike, a third between 6 and 15 and a third more than 15. The average number of viable seeds/spike for all samples was 13. Spikes from spring barley (152 samples) had an average of 11 and a maximum of 51 viable seeds and those from winter wheat (42 samples), 20 and 48 respectively. Samples collected within 3 weeks after mid-July had fewer viable seeds/spike than those collected later. Samples containing morphologically-different spikes had more viable seeds/spike than apparently uniform samples, and spikes from dense field populations more seeds than those from sparse populations. 相似文献
6.
P. T. Walker 《Pest management science》1971,2(6):267-275
Hessian fly was controlled to a maximum of 95% with organophosphate insecticides, in terms of the number of puparia and percentage tiller infestation at harvest. Granules: phorate at 1.68 kg/ha (1 1/2 lb/acre) as 10% granules in the seed furrow was most effective on durum wheat in 1967–8, with 69–92%, control, of tillers infested. 1.12 kg/ha gave 74–89% control, 0.56 kg/ha in the seed furrow 35–54%. Seed furrow treatment was more effective than band or broadcast treatment over young plants, although granules broadcast over young barley at 1.68 kg/ha of phorate gave 74% control in 1967–8. Fonofos (Dyfonate) granules at 1.55 kg fonofos/ha were most effective on barley in 1968–9, with 66% control. After fonofos and phorate, disulfoton at 1.68 kg disulfoton/ha was next in effect, with up to 86%, control in 1967-8 and 24% in 1968–9, but variable and not much more effective than at 0.56 kg/ha. Other insecticides were less effective. Seed dressings: disulfoton was the most effective, giving 79% control in 1967-8 on wheat and 77% on barley at a high rate of application that was phytotoxic in 1968–9. Diazinon, bromophos and ethion gave 15–38%, control and chlorfenvinphos and dimethoate less. Carbaryl dust at 1.12 kg carbaryl/ha gave 32% control. Yields were poor, but grain yield was increased by up to 33% in wheat in 1967-8, averaging about 15%. Barley yield was increased by 7% in 1967–8, and from 9–23% in 1968-9 by fonofos and phorate granules. Insect control reduced the number of tillers, increased the number of heads and increased the grain weight per head. In observation plots, chlormequat (CCC) spray alone at the 5-leaf stage reduced infestation of wheat by between 22% and 43%, but CCC with fertilizer, and fertilizer alone had no conclusive effect. High fly populations are partly due to leaving crop residues in the field at harvest. When these can be ploughed in, infestation should decrease. The use of insecticides may not be economic unless more consistent increases in yield can be obtained. 相似文献
7.
E. E. SCHWEIZER 《Weed Research》1976,16(1):37-42
Persistence of ethofumesate [(±)2-ethoxy-2.3-dihydro-3,3-dimethylbenzofuran-5-yl-methansulphonate] in soil was associated with soil temperature. Ethofumesate applied at 4.5 kg/ha in November persisted about twice as long in soil as that applied the following March. In another field study, 88–91% of the herbicide had dissipated after 24 weeks in sandy loam soil, compared to 72–77% in loam soil when it was applied at rates of 2.2, 3.4, 4.5, and 9.0 kg/ha. The rate of degradation was independent of the initial rate of chemical applied. The time required for 50% of the herbicide to dissipate in sandy loam and loam soils was 7.7 and 12.6 weeks, respectively. The movement of ethofumesate in these two soils over a 24-weeks sampling period was confined mainly to the upper 7.5 cm of the soil profile. 相似文献
8.
C. N. GIANNOPOLITIS 《Weed Research》1979,19(2):95-100
Hmergence of dodder (Cuseuta australis R. Br.) was unexpecledly prevented in plois of a sugarbeet field where ethofumesate had been applied at 1.6 Kg/ha. Appropriate laboratory tesls have shown that ethofumesate is a potent inhibitor of dodder seed germination (I D50= 10 μg/ml) and of early stem elongalion (ID50= 73μg/ ml). Wheat. a standard susceptible species to field applications of ethofumesate, is equally susceptible to inhibition of stem elongation (ID50=68 μg/ml), but it is far less susceptible to inhibition of germination (I D50=188 μg/ml). Compared to propyzamide. ethofiimesate is a stronger inhibitor of germination. Metolachlor and Hercules 22234 [eihyl N-chloroacetyl-N-(2,6-diethylphenyl) aminoacetate] are also active in inhibiting dodder germination and stem elongation, but at higher concentrations than ethofumesate. Current methods of controlling dodder in sugarheets may be improved with inclusion of pre-emergence use of ethofumesate. 相似文献
9.
Dissipation of dithiopyr in soil was monitored after application to wheat crop as pre- or post-emergence applications at two rates, viz 100 and 200 g AI ha(-1). The level of dithiopyr in the soil was assessed by gas chromatography, and its disappearence was found to follow a first-order decay curve irrespective of rate or method of application. The half-life in soil ranged between 17.3 and 25.0 days and residues at harvest (150 days after application) ranged between 4.0 and 8.8% of amounts applied. Investigation of microbial degradation of dithiopyr was conducted in minimal salt and Czapek Dox media in which 80% of the compound degraded within 15 days. Residues were not detected in wheat grain at harvest. 相似文献
10.
J. Pinowski 《EPPO Bulletin》1973,3(1):107-109
From the point of view of Polish agriculture, the rook (Corpus frugilegus L.) causes the most damage. Jackdaws (C. monedula L.) usually forage together with rooks and are equally abundant as a breeding species in the southern and central regions of Poland. Fields under spring oats, barley, wheat, maize, peas and winter wheat are the main feeding grounds of rooks and jackdaws. Unlike the corvine birds, starlings (Sturnus vulgaris L.), in Poland, only cause damage to cherry orchards, although in certain areas they also attack strawberries and currants. The house sparrows (Passer domesticus L.) cause considerable damage to ripening crops of wheat, barley, and sunflowers. Domestic pigeons cause considerable damage to crops of peas, wheat and maize grown within a 50 km radius of a town. 相似文献
11.
Residual effects of triadimefon in soil on powdery mildew and yield of spring barley 总被引：1，自引：1，他引：0
Residual triadimefon (or a breakdown product), from a spray application (2 kg/ha) to field soil in 1978, significantly decreased powdery mildew on spring barley throughout two subsequent growing seasons, with consequent yield increases of 42% in 1980 and 18% in 1981.
In other field experiments triadimefon applied to soil at rates >0.06 kg/ha decreased mildew in barley growing in the soil 11 months later. In these experiments triadimefon, but not benomyl, imazalil or prochloraz (all at 0.5 kg/ha) significantly decreased mildew up to harvest and increased yield by 22%.
Triadimefon incorporated into a loam soil and a peat-based compost at rates >0.1 ng/g significantly decreased mildew on barley grown in pots under glasshouse conditions. Plants grown in the treated compost at the same time but in isolated pots supplied with filtered moistened air and capillary watering required more triadimefon (>100 ng/g) in soil for significant mildew control.
Despite strong adsorption of triadimefon to soil (Kd 19.4), an active substance appears to remain available for uptake and translocation by barley plants over long periods. The sensitivity of barley mildew to extremely small residues of triadimefon is discussed in relation to the siting of field experiments on mildew control. The implications for widespread commercial use of formulations containing triadimefon are discussed in relation to disease control practice in cereal growing systems. 相似文献
In other field experiments triadimefon applied to soil at rates >0.06 kg/ha decreased mildew in barley growing in the soil 11 months later. In these experiments triadimefon, but not benomyl, imazalil or prochloraz (all at 0.5 kg/ha) significantly decreased mildew up to harvest and increased yield by 22%.
Triadimefon incorporated into a loam soil and a peat-based compost at rates >0.1 ng/g significantly decreased mildew on barley grown in pots under glasshouse conditions. Plants grown in the treated compost at the same time but in isolated pots supplied with filtered moistened air and capillary watering required more triadimefon (>100 ng/g) in soil for significant mildew control.
Despite strong adsorption of triadimefon to soil (Kd 19.4), an active substance appears to remain available for uptake and translocation by barley plants over long periods. The sensitivity of barley mildew to extremely small residues of triadimefon is discussed in relation to the siting of field experiments on mildew control. The implications for widespread commercial use of formulations containing triadimefon are discussed in relation to disease control practice in cereal growing systems. 相似文献
12.
The herbicide benfuresate applied preplanting to cotton (Gossypium hirsutum L.) fields infested with purple nutsedge (Cyperus rotundus L.) inhibited nutsedge growth for several weeks and was found selective for cotton. The best nutsedge control was achieved
when the herbicide was mechanically incorporated following a preplant broadcast or band application which was activated by
a sprinkler irrigation. The rate of benfuresate needed for effective and selective nutsedge control in cotton ranged from
0.80 to 1.60 kg/ha, the higher rates necessary in soils with higher clay and organic matter contents. 相似文献
13.
Losses in grain yield prevented by controlling weeds were measured in 59 fields of (southern hemisphere) spring-sown wheat (Triticum aestivum L.) (cv, Otane) and 45 fields of spring-sown barley (Hordeum vulgare L.) (cv. Corniche) in five consecutive growing seasons from 1988/89 until 1992/93 in the Canterbury region of New Zealand. The losses were measured as the differences in yield between weeded and non-weeded plots located in randomly positioned pairs in the fields. In the first 2 years, the weeding was by push hoe in‘organically grown crops. For the last 3 years, the fields were under prophylactic herbicide regimens with nonweeded plots created by excluding commercial herbicide applications (made mostly in October for wheat and November for barley) with polyethylene sheets placed temporarily over the plots. For each season the distributions of yield losses were modelled using the normal distribution and probabilities of ‘breaking even’ on herbicide use derived by substituting cumulative probability density functions into a simple break-even model for herbicide use. The model assumed that herbicide application in the current crop has no flow-on economic effect for succeeding crops. The mean annual yield losses prevented by herbicide application were positively correlated with September and October rainfall for wheat and bailey respectively. As a consequence, the probabilities of breaking even on herbicide use increased with increasing spring rainfall. Using historical rainfall records, probabilities of breaking even were estimated for each of the 48 years from 1947 to 1994. Averaging over these years, the analysis revealed that at current grain prices prophylactic use of the commonly applied herbicides is likely to be uneconomic in 24% (95% confidence limits 6% and 50%) of fields of average-yielding Otane wheat and in 26% (95% confidence limits 1% and 91 %) of fields of average-yielding Corniche barley in Canterbury. It was concluded that there is potential for withholding herbicide treatments without jeopardizing profitability in these crops, particularly in seasons with low spring rainfall. 相似文献
14.
J Petersen 《Weed Research》2003,43(1):33-39
Summary The experiments were carried out in the two spring barley fields of the organic six-course cattle:crop rotation at Foulumgaard, Denmark. The weed density was 300 and 1800 plants m−2 respectively. Pig slurry was applied by hand in microplots by four methods: broadcasting followed by incorporation, or injected in bands to depths of 5, 10 or 15 cm. Spring barley and weeds were sampled separately six times during the tillering and elongation phase of the spring barley. The effect of application method on dry-matter (d.m.) production, nitrogen uptake and recovery of applied nitrogen in the spring barley and the weeds is reported. Slurry banding halved the weed d.m. and weed N uptake compared with broadcasting, irrespective of weed density. Weeds recovered up to 12% of the applied nitrogen, which made them a significant competitor when the slurry was broadcast and incorporated. Banding by direct injection reduced the slurry:soil contact and the weed:crop competition balance for applied nitrogen moved in favour of the crop. Thus, the crop recovery of applied nitrogen at the end of the sampling period was increased from approximately 45% for broadcast and incorporated to approximately 50% for injected slurry, and coincidental weed recovery was reduced to a maximum of 5%. As the nitrogen supply normally affects plant d.m. production, banding of slurry might well improve crop competitiveness and its tolerance to mechanical weed control. 相似文献
15.
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.
16.
The aim of this study was to investigate how big a proportion of the spray liquid applied in a typical application was deposited on the soil surface below the crop. From an agronomical point of view this part of the spray is an undesirable loss of foliar acting pesticides during application and it also constitutes a primary source of leaching and surface run‐off. The investigation was carried out during 1998–2001 in winter wheat and in spring barley. Applications were carried out at approximate intervals of 10 days during the whole growing season in the two cereal crops. The results showed that a high proportion of the spray liquid reaches the soil below the crop during applications at early growth stages corresponding to the growth stages where weed control on farms is carried out. At later growth stages soil deposition declined and reached values below 5% of the applied dose in winter wheat after inflorescence emergence (50–59 BBCH). The spring barley crops remained more open and minimum soil deposit values were approximately 15% of the applied dose at growth stages (50–59 BBCH). During ripening soil deposition values increased again as crop cover decreased. 相似文献
17.
S. R. MOSS 《Weed Research》1983,23(1):45-51
Seed shedding from heads of Alopecurus myosuroides occurred from late June to late August at most locations. Most seeds were shed before winter wheat (Triticum-aestivum L.) was harvested hut at two winter barley (Hordeum sativum L.) sites, only 50% of seed was shed prior to harvest. The viability of seeds shed at the start and end of the shedding period tended to be lower than that at peak shedding time in late July and early August. There were large differences between sites in the viability of the total amount of seed shed. The results of viability tests based on the presence of full caryopses and germination in pots of sterile soil were similar. Assessments of head numbers and head length were significantly correlated with total seed production. Head length, but not head number assessments, were also significantly correlated with viable seed production. 相似文献
18.
In Northern Europe, inter-row hoeing has become a popular tactic for controlling weeds in organic cereals. Hoeing is highly effective and can be implemented from crop emergence until stem elongation to maintain a nearly weed-free inter-row zone. However, hoeing has a lesser effect on weeds growing in the intra-row zone, where crop–weed proximity results in heightened competition. In the hoed cereal system, it is investigated whether tall-growing, competitive, cruciferous weeds in the intra-row zone affect crop biomass, yield and thousand kernel weight (TKW). An additive experimental design is employed to enable the fitting of rectangular hyperbolas, describing and quantifying the effects of increasing intra-row surrogate weed density on crop growth parameters. Regressions were studied under the influence of crop (spring barley and spring wheat), row spacing (narrow [12.5 or 15.0 cm] and wide [25.0 cm]) and nitrogen rate (50 and 100 kg NH4-N/ha). Cruciferous surrogate weeds were found to impact crop yield and quality severely. For example, ten intra-row plants/m2 of surrogate weed Sinapis alba reduced grains yields by 7%–14% in spring barley and by 7%–32% in spring wheat with yield losses becoming markedly greater in wheat compared to barley as weed density increases. Compared to wheat, barley limited yield and quality losses and suppressed intra-row weed growth more. Row spacing did not have a consistent effect on crop or weed parameters; in one of six experiments, the 25 cm row spacing reduced yields and increased intra-row weed biomass in wheat. Nitrogen rate did not affect crop or weed parameters. Results warrant the implementation of additional tactics to control intra-row weeds and limit crop losses. 相似文献
19.
Host plant preference of the Russian wheat aphid Diuraphis noxia (Kurdj.) was studied on 11 cultivars of 9 plant species: winter barley, spring barley, winter wheat, spring wheat, rye, oat, Triticale, canary grass, red millet yellow millet and maize. Seeds of the host plants were sown in a circle near the edge of pots. The host plant choice was evaluated 24 hours after releasing 55 Diuraphis noxia female adults in the middle of each pot. The suitability of different hosts for aphid development was evaluated 2, 7 and 14 days after infestation based on the mean number of Russian wheat aphid individuals per plant. Red millet, yellow millet and maize were chosen by significantly fewer aphids than grain crops. Winter and spring barley were chosen as hosts most frequently, and the progeny production was also the highest on these plants. The growth rate of D. noxia was significantly affected by the host plants and the date of assessment and their interaction. 相似文献
20.
为了评价氟环唑在小麦生产上使用的残留安全性,建立了气相色谱-电子捕获检测器检测氟环唑在小麦植株、小麦籽粒及土壤中残留的分析方法,并对氟环唑在小麦植株、小麦籽粒和土壤中的最终残留量及小麦植株和土壤中的消解动态进行了研究。结果表明:在添加水平为0.01、0.1和2 mg/kg（小麦籽粒和土壤）和0.01、0.1和10 mg/kg（小麦植株）下,氟环唑的回收率为82%~93%,相对标准偏差为3.0%~9.7%。氟环唑在小麦植株、小麦籽粒和土壤中的定量限均为0.01 mg/kg。氟环唑在小麦植株和土壤中的消解半衰期分别为3.5~8.4和10~30 d。当以有效成分112.5 g/hm2的剂量施药2次、采收间隔期为21 d时,小麦籽粒中氟环唑的残留量为<0.05 mg/kg,低于中国制定的小麦中氟环唑的最大残留限量值（0.05 mg/kg）。建议氟环唑在小麦上使用时最大剂量为有效成分112.5 g/hm2,施药2次,安全间隔期为21 d。 相似文献