萎锈灵在大麦和土壤中的残留及安全性评价

为探明萎锈灵在大麦上的残留特性和安全性,通过田间试验和室内检测,研究了萎锈灵在大麦和土壤中残留的检测方法、萎锈灵在土壤中的消解动态及其在大麦和土壤中的最终残留量。结果表明,本检测方法对萎锈灵的最小检出量为0.002ng,萎锈灵在大麦植株、籽粒和土壤中的最低检测浓度分别为0.005、0.002、0.001mg·kg~(-1),添加回收率分别为78.9%~94.0%、92.4%~98.6%和90.6%~101.3%;相对标准偏差分别为1.3%~7.9%、1.8%~4.7%和0.9%~4.8%。萎锈灵在土壤中的半衰期为6.5~7.1d,药后14d消解率大于93%。400g·L~(-1)萎锈·福美双悬浮剂120、180g a.i.·100kg~(-1)种子拌种,收获期大麦籽粒中萎锈灵残留量均低于0.002mg·kg~(-1),说明400g·L~(-1)萎锈·福美双悬浮剂在大麦上使用是安全的。     

Response of Hordeum distichon cv. Igri (2-row) and H. hexastichon cv. Plaisant (6-row) winter barley to foliar applications of chlormequat

Two-row (cv. Igri) and six-row (cv. Plaisant) winter barley cultivars were incorporated into a field trial at Sutton Bonington (1984–1985) where the effects of chlormequat (CCC) applied at the three-leaf stage (main stem) and the onset of stem elongation were compared. CCC had no influence on lodging as the area cropped with ‘Igri’ completely lodged while no lodging occurred for the cultivar ‘Plaisant’.Neither CCC treatment nor cultivar influenced the rate, duration or pattern of biomass accumulation. CCC application in either the autumn or spring increased harvest index and thus grain yield for both genotypes. Mean grain mass linearly declined as ear population was increased by CCC application, with the number of grains per ear unchanged. A parabolic response of grain yield to the number of ears was inferred and an analysis was used to determine the optimum ear density.     

Resistance to carboxin and fenfuram in Ustilago nuda (Jens.) Rostr., the causal agent of barley loose smut

Two types of strains of Ustilago nuda, resistant to carboxin and fenfuram, were detected on winter barley crops in 1986. The most frequent strains are similar to those found previously and they are characterized by their great susceptibility to mepronil and flutolanil. This negative correlation between two groups of carboxamide fungicides is not found when the other type of carboxin-resistant isolates is considered. From these observations, we elaborate a simple teliospore-germination test which can be used for routine survey of resistance. In field trials, when the resistant strains are prevalent (in the absence of treatment), the efficacy of seed dressings with carboxin or fenfuram against barley loose smut is low. In such situations, which are common with the winter barley varieties Panda or Viva, inhibitors of sterol biosynthesis such as flutriafol or triadimenol remain very active in practice.     

Control of Helminthosporium leaf blight of spring wheat using seed treatments and single foliar spray in Indo-Gangetic Plains of Nepal

Four fungicides for seed treatments and one as foliar spray were tested in replicated field experiments in a strip plot design to determine the effect of fungicides on Helminthosporium leaf blight (caused by Cochliobolus sativus and Pyrenophora tritici-repentis) severity and grain yield of wheat. Wheat seed cv. RR 21 was treated with fungicides, carbendazim (Areestin), triadimenol (Baytan), tebuconazole (Raxil), and carboxin + thiram (Vitavax 200B). Single foliar application of propiconazole (Tilt) was sprayed at flowering stage. Controls were included for both factors and treatments were replicated four times. Triadimenol and carboxin + thiram increased seed germination in both years. Triadimenol, tebuconazole, and carboxin + thiram reduced the number of infected seedlings and seedling root rot severity in both years. Number of tillers was higher in carboxin + thiram treated plots compared to other seed treatments. Compared to the control, carboxin + thiram increased grain yield by 9% and 8% in 2004 and 2005, respectively, and triadimenol by 6% in both years. The foliar spray of propiconazole significantly reduced Helminthosporium leaf blight severity and increased thousand-kernel weights. Propiconazole spray increased grain yield by 15% and 14% in 2004 and 2005, respectively. Therefore, seed treatment either with triadimenol or carboxin + thiram in combination with single post-flowering foliar spray of fungicides should minimize grain yield loss due to wheat foliar blight in South Asia. The findings of this study could be useful in developing strategies to manage Helminthosporium leaf blight in South Asia and other warm wheat growing regions of the world.     

Influence, optimization, energy budgeting and monetary considerations of different time intervals between fungicidal seed treatment and sowing on Sclerotium blight of soybean

Soybean (Glycine max (L.) Merrill) is susceptible to the fungal pathogen, Sclerotium rolfsii from seedling emergence to pod fill. A few systemic and non-systemic fungicides have been recommended as pre-sowing seed treatment (ST) for the management of Sclerotium blight of soybean worldwide. But farmers, especially in developing countries do not utilize ST mainly on account of preoccupation in other practices considered by them essential for sowing. The possibility of ST applied well in advance of sowing was therefore investigated. Results indicated that ST on average increased field emergence by 26.19%, reduced post-emergence mortality (POM) by 49.03% and enhanced seed yield by 23.00%. Seed treatment with carboxin 37.5% + thiram 37.5% @ 0.2% was the best. Seed treatment 50 days prior to sowing was superior by increasing emergence, reducing POM and enhancing seed yield with high monetary returns and energy output.     

Rhizoctonia seedling disease of hemp and its control

Rhizoctonia solani Kuhn was isolated from hemp (Hibiscus cannabinus) seedlings affected by damping-off disease. The fungus was highly pathogenic on artificial inoculation. There is no earlier record of this disease in Iraq. Of nine fungicides tested as seed treatment, Bavistin (carbendazim), Homai (thiram), Vitavax (carboxin), Topsin (thiophanate), Fundazol and Benlate (benomyl) gave effective control of the disease.     

冬灌与化学调控互作对滴灌春小麦抗倒伏能力和产量的影响

为给滴灌春小麦高产抗倒伏栽培提供参考依据,以新疆地区主栽品种新春6号和新春19号为材料,研究了冬前灌溉与化学调控互作对滴灌春小麦抗倒伏能力和产量的影响。结果表明,冬前灌溉可促进滴灌春小麦植株干物质积累,增加产量,但降低抗倒伏能力。矮壮素浸种+分蘖期叶面喷施矮壮素能协调滴灌小麦地上和地下部分的生长,增强茎和根抗倒伏能力,且在两个品种上应用效果无差异;在此基础上配合冬灌能实现滴灌小麦抗倒和增产。     

Effect of chemical and biological treatments on take-all of winter wheat

Several chemical and biological treatments were evaluated for control of take-all, caused by Gaeumannomyces graminis var. tritici, on winter wheat (Triticum aestivum). None of the treatments resulted in an effective suppression of take-all (percentage of roots with symptoms or whiteheads) or an increase in yield in naturally or artificially infested field experiments over 3 years. In a controlled-environment study triadimenol, imazalil and a combination of carboxin and thiram reduced the percentage of plants infected, and inoculating soil with G. graminis var. graminis gave good control. Disease development in field studies was limited in the fall. The greatest disease development occurred in the spring with the increase in soil temperatures. The lack of control of take-all by fungicides, such as triadimenol, which have been reported to be effective in other studies is discussed in relation to the development of the disease in south-eastern USA.     

Effects of fungicides applied at seeding on stripe rust and common bunt of wheat

Control of stripe rust (Puccinia striiformis) and common bunt (Tilletia caries and T. foetida) of wheat (Triticum aestivum), with fungicides applied on or adjacent to seed at sowing, was studied. Etaconazole pellets (2800 g a.i./ha), fenfuram liquid seed treatment (17 · 5 g a.i./ha) and imazalil granules (5000 g a.i./ha) were phytotoxic, reducing the number of heads per plot. All treatments reduced the incidence of common bunt although benomyl granules (2500 g a.i./ha), benomyl pellets (1400 g a.i./ha) and imazalil granules (5000 g a.i./ha) were not as effective as the registered smut fungicides carboxin, fenfuram, fenaminosulf and triadimefon. Triadimefon pellets (7000 g a.i./ha), PP347 pellets (1400 g a.i./ha), triadimefon granules (1500 g a.i./ha), flutriafol pellets (1400 g a.i./ha) and etaconazole pellets (2800 g a.i./ha) reduced stripe rust severity 17 weeks after sowing by 90, 89, 88, 86 and 74%, respectively.     

Improvements to newly sown ryegrass by use of combined fungicide and insecticide treatment

Fungicide seed treatment using benomyl+captan, combined with postemergence sprays of the insecticides chlorpyrifos and omethoate increased herbage yield 10 weeks after sowing in five of eight sowings of Italian and perennial ryegrass. At one sowing, five other fungicide seed treatments—carbendazim+captan, thiabendazole+captan, thiabendazole+thiram, thiabendazole+metalaxyl, and drazoxolon—combined with the insecticide sprays, also increased yield. The insecticides were shown to give good control of shoot-fly larvae, but the yield response to insecticides alone was not as great as that from the combined treatment. As fungicide seed treatment alone increased seedling emergence at one sowing only, possibly the fungicides improved seedling vigour by reducing sub-lethal attacks from soil-borne diseases. The combination of a fungicide and insecticide seed treatment was used at five sowings with no effect.     

Effect of two plant growth regulators on the yield and quality of russet burbank potatoes

Summary Foliar applications of ethephon (ETH) 300 g a.i. ha⁻¹; chlormequat chloride (CCC) 920 g a.i. ha⁻¹, with a second application of 230 g a.i. ha⁻¹ approximately 2 weeks later; and a mixture of the two (ETH/CCC) 156 g a.i. ethephon and 299 g a.i. chlormequat chloride ha⁻¹ were made to field-grown Russet Burbank potatoes in 1986, 1987 and 1989. All the treatments increased the number of tubers set and reduced the average tuber weight compared to the control resulting in a reduction in premium and marketable tubers, and an increase in small tubers. Differences were greatest for ETH and least for CCC. ETH and ETH/CCC decreased the specific gravity, increased the incidence of deformities, and decreased the incidence of tubers with hollow heart. The growth regulators did not affect fry colour.     

Efficacy of fungicides againstColletotrichum coccodes on potato tubers

Summary Thirty three fungicides were evaluatedin vitro andin vivo for the control of anthracnose, caused byColletotrichum coccodes (Wallr.) Hughes. Three promising fungicides, thiram, captafol wp and sc and prochloraz, were identified by a filter paper-disc plate method, but only prochloraz had an effect when using a fungicide plate method. None of the fungicides adequately controlled anthracnosein vivo.     

大麦对大麦条纹病菌毒素胁迫的响应

为探究大麦条纹病菌毒素对大麦种子萌发、幼苗生长及防御酶活性的影响,用大麦条纹病菌毒素处理20个大麦品种的种子,测定120 h后毒素对种子的萌发抑制率和胚根、胚芽生长抑制率,并测定了强抗病性种子萌发48 h、72 h、120 h和168 h时的超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)的活性及游...     

Integrated management of major diseases of mungbean by seed treatment and foliar application of insecticide,fungicides and bioagent

Field experiments were conducted during the rainy seasons of 2009 and 2010 for the management of the major diseases of mungbean, namely, wet root rot (Rhizoctonia solani), cercospora leaf spots (Cercospora canescens and Pseudocercospora cruenta) and yellow mosaic (Mungbean Yellow Mosaic Virus) by using different combinations of an insecticide, fungicide, and bio-formulation as seed treatment, with or without foliar sprays. A combination of seed treatment with thiamethoxam (Cruiser™) at 4 g kg⁻¹, carboxin (Vitavax™) at 2 g kg⁻¹ and Pusa 5SD (Trichoderma virens) at 4 g kg⁻¹ followed by simultaneous foliar sprays of thiamethoxam (Actara™) 0.02% and carbendazim (Bavistin™) 0.05% at 21 and 35 days after sowing resulted in the highest seed germination and grain yield in mungbean with the lowest intensities of cercospora leaf spots and mungbean yellow mosaic, and moderate incidence of wet root rot. The lowest whitefly population was also observed in this treatment during all stages of the crop. The treatment combinations having Pusa 5SD as seed treatment provided the lowest wet root rot incidence. Two sprays were superior to single spray for all variables recorded, but in combination with seed treatment, single spray was found to be more cost effective as it obtained the highest return per rupee of input. Use of T. virens based bio-formulation Pusa 5SD with insecticide thiamethoxam has been effectively demonstrated for the first time along with fungicides Bavistin and Vitavax for the management of the major diseases of mungbean.     

Effects of fungicides used to control Rhynchosporium secalis where benzimidazole resistance is present

The effects of fungicides used to control Rhynchosporium secalis in winter barley were investigated in five field trials in Co. Down, Northern Ireland. Benzimidazole resistance was present in the R. secalis population of each site. Fungicide performance was evaluated in terms of disease control, maintenance of green leaf area, grain yield and grain quality. Samples of R. secalis isolates taken before and after treatment in each field were assessed for sensitivity to carbendazim in the laboratory. Carbendazim contributed little to disease control, the maintenance of green leaf area, grain yield or grain quality. Carbendazim was associated with a significant increase in disease severity in some plots. Treatments containing carbendazim, either alone or in mixture, caused an increase in the proportion of carbendazim-resistant isolates within R. secalis populations. Propiconazole-containing treatments performed well in terms of disease control, maintenance of green leaf area and grain quality. They caused no change in carbendazim resistance frequency.     

病毒诱导的全新tae-miR9663的沉默影响叶片发育和籽粒大小

MicroRNA(miRNA)是一类长度为18~24nt的非编码小分子RNA,参与植物各种发育进程。tae-miR9663是新发现的在小麦幼苗、旗叶和籽粒中高表达的miRNA,但其生物学功能未知。为了探索taemiR9663的功能,通过人工合成tae-miR9663的小串联模拟靶标(short tandem target mimic,STTM),将其构建到大麦条斑花叶病毒(barley stripe mosaic virus,BSMV)载体上,利用病毒介导的基因沉默(virus-inducing gene silencing,VIGS)技术转染小麦宁春16五叶一心期的第5片叶,转染20d后观察叶片表型并取旗叶进行实时定量PCR,成熟时观察种子大小。叶片表型观察结果表明,与BSMV:00相比,接种BSMV:STTM-taemiR9663的9株幼苗中出现4种叶片表型,即第6片叶有白点或白条纹,旗叶(第7片叶)有白点或白条纹,第6片叶边缘有锯齿状,旗叶叶尖处有皱缩。实时定量PCR分析结果表明,STTM-tae-miR9663过表达植株的tae-miR9663表达丰度下降,说明BSMV-VIGS技术可通过过表达STTM有效地沉默内源miRNA。成熟种子大小观察结果表明,与BSMV:00比较,接种BSMV:STTM-tae-miR9663的植株种子的长和宽均减小。     

植物生长调节剂拌种对扬麦13茎秆生长及籽粒产量的影响

为给高产小麦合理选用生长调节剂提供科学依据,以弱筋小麦扬麦13为试验材料,研究了不同生长调节剂(矮壮素、拌种剂、种衣剂、多效唑)拌种对不同群体小麦茎秆生长及籽粒产量的调节效应。结果表明,拌种处理均能有效降低扬麦13的株高、重心高度及基部节间长度,对茎秆粗度、茎壁厚度、茎秆干重的调节效应因生长调节剂种类不同而存在差异,其中,低密度条件下拌种剂处理的小麦茎壁厚度增加显著,而高密度条件下多效唑处理小麦的茎壁厚度增加显著。生长调节剂拌种处理提高了扬麦13的抗倒伏能力,其作用效果表现为多效唑种衣剂拌种剂矮壮素。相关分析表明,降低植株株高、基部第一节间长度,增加基部第一、二节间壁厚有利于提高植株抗倒性能。拌种处理下小麦产量均高于对照,300×104株·hm-2群体的产量高于150×104株·hm-2群体,均以种衣剂拌种处理增产最明显,平均增幅达11.68%,在倒伏年拌种处理增产效果更显著。     

The effect of seed-and soilborne inoculum ofColletotrichum coccodes on the incidence of black dot on potatoes

Summary Soil in a potato field naturally infested with black dot (Colletotrichum coccodes) was fumigated with methyl bromide at 126 g m⁻² or left unfumigated. Potato seed tubers (cv. BP1) uninfected, lightly infected (1–25% surface affected), severely infected (26–100% surface affected) and severely infected withC. coccodes but dusted with prochloraz manganese chloride as Octave 2.5% DP at 750 g per 100 kg seed were planted in fumigated and unfumigated soil. When harvested, the incidence of black dot on the progeny of infected seed planted in unfumigated soil was twice that of progeny in fumigated soil, with progeny of uninfected seed having a 68.5 times higher disease incidence in unfumigated soil. Black dot on progeny tubers was reduced by pre-treatment of seed with prochloraz in fumigated soil only. With black dot infested fields, planting disease-free seed or treating seed with fungicides would not decrease disease on progeny tubers.     

Relation of Leaf Nitrogen Content and Other Traits with Seed Yield of Soybean

Summary

Soybean redistributes or 201C;mobilizes” a large amount of its vegetative nitrogen in support of synthesis of seed storage protein. Most of this is from leaf tissue. Our objective was to elucidate the relationship between potentially mobilizable leaf nitrogen and seed yielding capacity of soybean. In each of two years, we grew 63 diverse soybean genotypes in a replicated field experiment. Whole plants were harvested from 1 m² of plot area. Leaf mass, leaf area index, and leaf nitrogen concentration were determined at beginning of seed growth (R5). Seed yield was obtained by combine harvest. Seed yields ranged from 2400 to 4400 kg ha^–1 the first year and from 2200 to 3800 kg ha^–1 the second. Total leaf nitrogen content at beginning of seed growth, after adjustment for differences in reproductive duration and lodging, accounted for 40 and 34% of genotypic variation in seed yield for the two years. Leaf mass, leaf area index, and leaf nitrogen concentration were less well related to yield. Reproductive duration, estimated as the time from beginning bloom to maturation, accounted for 30 and 20% of genotypic variation in seed yield, and lodging accounted for 21 and 23% for the two years. The three most important factors, total leaf nitrogen content at R5, reproductive duration, and lodging, as determined by multiple regression, accounted for 64 and 59% of genotypic variation in yield the two years. Hypothetical selection for total leaf nitrogen content at beginning of seed growth revealed a lack of consistency in genotypic performance between years, suggesting low heritability of the trait and therefore a low probability for improving the trait through plant breeding. We conclude that the failure of genotypes to perform similarly between years implies that the vegetative nitrogen pool is a very important, albeit secondary, source that is drawn upon variably in different environments depending upon the plant’s capacity to assimilate nitrogen directly.     

Effects of a range of fungicides used to control rust (Uromyces viciae-fabae) on spring-sown field beans (Vicia faba) in the UK

In two years a range of fungicides was used to control rust (Uromyces viciae-fabae) on spring-sown field beans (Vicia faba). In 1984 fenpropimorph, maneb, mancozeb, maneb plus mancozeb, propiconazole, thiram, triadimefon and zineb-polyethylene thiuram disulphide plus tridemorph were applied once or twice and compared with no fungicide. In 1985 the experiment was repeated with the addition of benodanil. In 1984 there was very little rust or other foliar disease and the effects of treatments on yield were small. In 1985 rust was first found in late June and became severe on untreated plots in August. All the fungicides reduced the incidence of rust but the amount of control differed with frequency of application and on different dates of disease assessment. In 1985 chocolate spot (Botrytis fabae) also became severe in late August. All the fungicides reduced chocolate spot but maneb plus mancozeb was the most effective. In 1985 yields were increased from 5 · 6 to 7 · 7 t/ha by maneb plus mancozeb applied once. Other fungicides gave smaller yield increases. Yield increases given were attributable mainly to control of rust but partly to control of chocolate spot. Yield increases given by non-systemic fungicides came mainly from increases in the weight of individual grains; those yield increases given by systemic materials came, in addition, from better pod retention.