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1.
Glasshouse experiments to test the activity of commercial fungicides against Septoria tritici were carried out under controlled conditions. In addition to the parameter, % necrotic leaf area (NEC), used to estimate the pathogen-induced leaf damage, the number of pycnidia per leaf (PYC) was determined to quantify the pathogen itself. Curative fungicide treatments were applied 100–210 day degrees after inoculation. A high curative activity was achieved up to 170 day degrees after inoculation, whereas the treatments at 200–205 day degrees were less effective. The best curative activity was observed for epoxiconazole-based treatments, followed by slightly less active azoles in the ranking tebuconazole, cyproconazole, prochloraz and flusilazole. Greater differences between the fungicides were observed for the protectant fungicide properties, which were tested 50–350 day degrees prior to inoculation. The best persistency was observed for epoxiconazole, whereas tebuconazole, cyprocoazole, prochloraz and flusilazole showed declining activity with this ranking. Combinations of triazoles with the active ingredients kresoxim-methyl and chlorothalonil, which are known to inhibit spore germination, significantly improved the longevity of the remaining green leaf area in comparison with disease-free treatments with triazoles alone. The results obtained under glasshous conditions were compared with field studies on S. tritici development after treatments with tebuconazole to place the results in context. The comparison of the assessment parameter PYC and NEC between glasshouse and field trial showed that curative and protectant fungicide properties based on microscopic assessments of PYC in the glasshouse correlated well with results from field trials. 相似文献
2.
Substantial reductions in winter wheat diseases caused by addition of straw but not manure to soil 总被引：2，自引：0，他引：2
Over a period of 3 years, five agronomically distinct crops of winter wheat were grown in plots in which straw (1 kg m−2 ), manure (4 kg m−2 ) or nothing were incorporated into the soil. Plant establishment and height, but not leaf area per tiller, were lower in straw-treated plots. Fertilizer regimes differed between years. Soil and leaf nitrogen were recorded; there was no obvious link between N and any disease or soil amendment. The numbers of leaf layers scorable for disease were similar in all treatments. At the end of the season, plants from straw-treated plots had consistently reduced septoria tritici blotch (caused by Mycosphaerella graminicola ), powdery mildew [caused by Erysiphe ( Blumeria ) graminis ], brown rust (caused by Puccinia recondita ) and foot rot (caused by Fusarium spp.). Early on, M. graminicola was worse in straw-treated plots. In manure-treated plots, P. recondita was reduced but effects on other diseases were inconsistent and slight. A fungicide, chlorothalonil, was applied in one crop; its effects did not interact with those of other treatments. Mycosphaerella graminicola was not suppressed by straw in outdoor pot experiments. Late in the season, straw-treated plants had significantly higher leaf silica ( P < 0·01). In a glasshouse experiment, plants supplied with silicon had less E. graminis infection ( P < 0·001) and higher leaf silica, but effects on M. graminicola were inconsistent. A prior inoculation of M. graminicola primed plant defences against a subsequent attack of E. graminis , but only in the presence of adequate Si. It is postulated that straw acts in the field by increasing Si availability. 相似文献
3.
The effect of foliar-applied potassium chloride on Septoria tritici , the anamorph of Mycosphaerella graminicola , was quantified and possible modes of action investigated during controlled-environment and field experiments. A field experiment in harvest year 1997 showed c . 50% reduction in the area of leaf 2 of winter wheat plants affected by septoria leaf blotch after foliar application of potassium chloride, compared with untreated controls. Similarly, in harvest year 1998 potassium chloride reduced, by about one-third, the area of the flag and penultimate leaf affected by S. tritici . However, a significant yield increase was not observed, although grains m−2 did show an increase of borderline significance. Applications of epoxiconazole reduced the area of leaf 4 affected by S. tritici compared with untreated controls, whereas applications of chlorothalonil, potassium chloride or polyethylene glycol proved ineffective against disease development. This may suggest that potassium chloride is relatively immobile and possesses contact activity similar to that of chlorothalonil. In 1998, similar reductions in leaf area affected were observed with the inert osmoticum polyethylene glycol in the field, suggesting that the control provided by potassium chloride may be achieved by adverse osmotic effects on the pathogen. Scanning electron microscopy of germinating conidia on wheat plants showed inhibition of conidial germination by both potassium chloride and polyethylene glycol at the same calculated osmotic potential on the leaf surface. 相似文献
4.
5.
Green fluorescent protein (GFP)‐expressing transformants were used to investigate the effects of strobilurin fungicide azoxystrobin on Mycosphaerella graminicola infection. Azoxystrobin treatments (125 or 250 g AI ha?1) were applied at various stages of the infection process under controlled conditions. GFP transformants showed conserved in vitro sensitivity to azoxystrobin and pathogenicity. Azoxystrobin controlled over 90% of M graminicola infections when applied before or during penetration of the pathogen (15% of the incubation phase). Azoxystrobin also impaired the growth of intercellular hyphae in M graminicola post‐penetration infection stages when applied at up to 50% of the incubation phase. Incubating infections observed in treated leaves were viable, but their growth was impaired and they did not induce necrosis under controlled conditions. Reduction by half of azoxystrobin dosage had little or no effect on azoxystrobin efficiency in controlling M graminicola. The contribution of post‐penetration fungistatic effect to azoxystrobin curative properties toward M graminicola in a field situation is discussed. © 2001 Society of Chemical Industry 相似文献
6.
嘧菌酯对扁豆纹枯病的物理作用方式及其生物动力学特性 总被引：2，自引：0，他引：2
以多菌灵和福美双为对照药剂,测定了嘧菌酯对立枯丝核菌Rhizoctonia solani的抑制活性,并用离体叶片法测定了嘧菌酯对该病原菌引起的扁豆纹枯病的物理作用方式及其生物动力学特性。嘧菌酯、多菌灵和福美双对立枯丝核菌菌丝生长的EC50值分别为0.072 4、1.134 4和1.202 6 μg/mL。施药后立即接种, 250 μg /mL嘧菌酯、500 μg /mL多菌灵和1 000 μg /mL福美双对扁豆纹枯病的保护效果分别为95.61％、99.88％和81.45％;施药3 d后再接种,嘧菌酯、多菌灵和福美双对扁豆纹枯病的保护效果分别为92.27％、100％和46.96％;接种36 h后再施药,3种药剂对扁豆纹枯病的治疗效果分别为90.40％、95.75％和61.94％。表明嘧菌酯对扁豆纹枯病具有很好的保护作用、持效性和治疗作用。在叶片基部施药后在顶部接种,嘧菌酯、多菌灵和福美双对扁豆纹枯病的防治效果分别为87.81％、42.09％和7.24％;在叶片背面施药后在正面接种,3种药剂对扁豆纹枯病的保护效果分别为87.30％、37.00％和16.15％。表明嘧菌酯在扁豆叶片中具有很好的木质部输导和跨层转移活性。 相似文献
7.
There is increased awareness of the need to clean the external surfaces of sprayers, but the extent to which the washings may impact on the environment is not known. Quantification of the levels of external residues on sprayers could give an indication of the potential environmental impact of sprayer cleaning. The presence of azoxystrobin, carbendazim, chlorothalonil, cyanazine, cypermethrin, epoxiconazole, flusilazole, isoproturon, kresoxim-methyl, metazachlor, pendimethalin, pirimicarb and tebuconazole on thirteen sprayers, sampled on two occasions was investigated. Composite samples were taken from the boom, nozzles and spray tank (delivery system) and the mudguard, cab door, rear window and windscreen (tractor body). Despite being subject to some form of cleaning, pesticides were detected on all sprayers. Residues were found at higher quantities and with greater frequency on the nozzles and booms, but the mean dose on the spray tank was equal to that on the mudguard (7.2 mg m(-2)). Isoproturon, pendimethalin, metazachlor, chlorothalonil and azoxystrobin were all detected above 1000 mg m(-2) on the delivery system, whereas on the tractor body the highest concentrations were between 100 and 1000 mg m(-2) (isoproturon, pendimethalin, chlorothalonil and carbendazim). On the whole, azoxystrobin was detected on the least number of occasions. However, there was great variation within and between compounds and sampling sites. Generally sprayers were not cleaned frequently or efficiently, enabling residues to accumulate on the external surfaces where they can remain for years. The findings here indicate that the quantity of these residues may be sufficient to be harmful to aquatic organisms should the residues enter a watercourse. In addition, if all the residues were removed by cleaning in the field and the washings catchment area was 15 m2 or less, overdosing could occur. Further work is required to assess whether a more frequent cleaning regime would reduce the overall environmental impact of cleaning sprayers. Implications for potential occupational exposure are considered elsewhere. 相似文献
8.
Pre- and post-infection activities of phosphonate and fungicides (azoxystrobin, chlorothalonil, cyazofamid, copper hydroxide, and copper sulfate) against white powdery rot on fig leaves caused by Phytophthora palmivora were determined. Phosphonate and fungicides were applied at 3, 7, or 14 days before inoculation and 16, 24, or 40 h after inoculation. Phosphonate and four fungicides (except for chlorothalonil) had protectant activity for up to 14 days before inoculation. Protectant activity between phosphonate and the four fungicides did not differ significantly. These fungicides did not have a curative activity, whereas only phosphonate had a curative activity when applied 16 h after inoculation. The pre-infection activity of phosphonate was determined in fig fields. Phosphonate provided excellent protectant activity, and its activity did not differ significantly from that of the copper fungicides. The activity of phosphonate in the life cycle of P. palmivora was compared with that of the five fungicides. Half-maximal effective concentration of the inhibition of mycelial growth was low for phosphonate, chlorothalonil, and the two copper fungicides. Mycelial growth was least affected by azoxystrobin and cyazofamid, but n-propyl gallate, an alternative oxidase inhibitor, in combination with these fungicides, significantly inhibited mycelial growth. Sporangium formation was sensitive to all compounds. Germination of encysted zoospores was sensitive to azoxystrobin, cyazofamid, and chlorothalonil and least sensitive to phosphonate and the two copper fungicides. The activity of phosphonate on mycelial growth and sporulation of P. palmivora suggests it has potential for controlling the disease. 相似文献
9.
BACKGROUND: Management of early leaf spot (Cercospora arachidicola Hori.), late leaf spot [Cercosporidium personatum (Berk. & MA Curtis) Deighton] and stem rot (Sclerotium rolfsii Sacc.) of peanut (Arachis hypogaea L.) in the southeastern USA is heavily dependent upon sterol biosynthesis inhibitor (SBI) and quinone outside inhibitor (QoI) fungicides. Effective new fungicides with different modes of action could improve overall disease control and extend the utility of the current fungicides. Penthiopryad is a pyrazole carboxamide fungicide being evaluated for use on peanut. Field experiments were conducted from 2004 to 2007 to determine the effect of a range of rates (0–0.36 kg AI ha?1) of penthiopyrad on leaf spot and stem rot and the relative efficacy of penthiopyrad and current fungicide standards chlorothalonil, tebuconazole and azoxystrobin. RESULTS: Leaf spot control in plots treated with penthiopyrad at 0.20 kg AI ha?1 or higher was similar to or better than that for the chlorothalonil standard. The incidence of stem rot for all penthiopyrad treatments was usually less than that for the tebuconazole or azoxystrobin standard treatments. Pod yields for all penthiopyrad treatments were similar to or higher than those for the respective standards. CONCLUSION: Penthiopyrad has excellent potential for management of late leaf spot and stem rot of peanut, and may complement current SBI and QoI fungicides. Copyright © 2008 Society of Chemical Industry 相似文献
10.
The effects of varying doses of fungicides, alone or in mixtures, on selection for triazole resistance were examined under field conditions. Two experiments were conducted using the triazole fungicide fluquinconazole with the strobilurin fungicide azoxystrobin as a mixture partner. Inoculated wheat plots with a known ratio of more sensitive to less sensitive isolates of the leaf blotch fungus Mycosphaerella graminicola were sprayed with fungicide and sampled once symptoms had appeared. Selection for fluquinconazole resistance increased in proportion to the dose, up to one-half of the full dose (the maximum tested) in both experiments. At the higher doses of fluquinconazole, the addition of azoxystrobin was associated with a decrease in selection (nonsignificant in the first experiment) for triazole resistance. Control by low doses of fluquinconazole was increased by mixture with azoxystrobin, but at higher doses mixture with azoxystrobin sometimes decreased control, so that reduced selection was obtained at the cost of some reduction in control. The effects on resistance are not necessarily general consequences of mixing fungicides, and suggest that the properties of any specific mixture may need to be demonstrated experimentally. Selection was inversely related to control in the unmixed treatments in both experiments, but the relationship was weaker in the mixtures with azoxystrobin. 相似文献
11.
Forty-six (1.5%) of nearly 3000 isolates of Mycosphaerella graminicola assayed in vitro were resistant to the QOI fungicide azoxystrobin, but on sub-culturing only ten remained resistant. Cross-resistance extended to other QOIs, but varied between different isolates. In planta the resistant isolates were not well controlled, especially at lower azoxystrobin dose rates. Propyl gallate, an inhibitor of alternative oxidase, potentiated the activity of azoxystrobin in vitro so that resistance was no longer observed. The growth of resistant strains in the presence of azoxystrobin led to alternative oxidase activation. This increased flexibility in respiration allows resistant strains to survive in the presence of a QOI fungicide. Under these conditions, selection for target-site mutations can occur. Using QOIs preventatively reduces the risk of resistance since the alternative oxidase cannot by itself generate all the energy needed for germination and early infection. 相似文献
12.
Yu Chen Jian Yao Wen-Xiang Wang Tong-Chun Gao Xue Yang Ai-Fang Zhang 《European journal of plant pathology / European Foundation for Plant Pathology》2013,135(4):675-682
Sensitivity to epoxiconazole of 90 single-spore isolates of Magnaporthe oryzae was determined. The EC50 values for epoxiconazole in inhibiting mycelial growth of the 90 M. oryzae isolates were 0.11–0.86 μg/ml, with an average EC50 value of 0.260?±?0.082 μg/ml. There was no correlation between sensitivity to epoxiconazole and sensitivity to carbendazim or iprobenfos. In protective and curative tests, epoxiconazole applied at 200 μg/ml provided over 70 % control efficacy, while tricyclazole exhibited better protective than curative activity. The results of four field trials performed in 2010 and 2011 at two sites showed that epoxiconazole at 112.5 g a.i/ha provided over 75 % control efficacy, which was similar to tricyclazole with 300 g a.i./ha and better than carbendazim with 562.5 g a.i./ha. 相似文献
13.
Fraaije BA Cools HJ Fountaine J Lovell DJ Motteram J West JS Lucas JA 《Phytopathology》2005,95(8):933-941
ABSTRACT Strobilurin fungicides or quinone outside inhibitors (QoIs) have been used successfully to control Septoria leaf blotch in the United Kingdom since 1997. However, QoI-resistant isolates of Mycosphaerella graminicola were reported for the first time at Rothamsted during the summer of 2002. Sequence analysis of the cytochrome b gene revealed that all resistant isolates carried a mutation resulting in the replacement of glycine by alanine at codon 143 (G143A). Extensive monitoring using real-time polymerase chain reaction (PCR) testing revealed that fungicide treatments based on QoIs rapidly selected for isolates carrying resistant A143 (R) alleles within field populations. This selection is driven mainly by polycyclic dispersal of abundantly produced asexual conidia over short distances. In order to investigate the role of sexually produced airborne ascospores in the further spread of R alleles, a method integrating spore trapping with real-time PCR assays was developed. This method enabled us to both quantify the number of M. graminicola ascospores in air samples as well as estimate the frequency of R alleles in ascospore populations. As expected, most ascospores were produced at the end of the growing season during senescence of the wheat crop. However, a rapid increase in R-allele frequency, from 35 to 80%, was measured immediately in airborne ascospore populations sampled in a wheat plot after the first QoI application at growth stage 32. After the second QoI application, most R-allele frequencies measured for M. graminicola populations present in leaves and aerosols sampled from the treated plot exceeded 90%. Spatial sampling and testing of M. graminicola flag leaf populations derived from ascospores in the surrounding crop showed that ascospores carrying R alleles can spread readily within the crop at distances of up to 85 m. After harvest, fewer ascospores were detected in air samples and the R-allele frequencies measured were influenced by ascospores originating from nearby wheat fields. 相似文献
14.
玉米病虫害是影响玉米产量和品质的重要因素。本研究选择2种杀虫剂(40%氯虫苯甲酰胺·噻虫嗪WG和100 g/L顺式氯氰菊酯EC)和4种杀菌剂(18.7%丙环唑·嘧菌酯SE、250 g/L吡唑醚菌酯EC、125 g/L氟环唑SE和17%吡唑醚菌酯·氟环唑SE),通过单独或组合在玉米心叶期(V12)一次性施药,并在药后7 d接种玉米弯孢菌,随后对各处理的防治效果和经济效益进行比较分析。基于施药成本、施药后的增产效益和玉米价格,采用贝叶斯推断统计方法计算净利润的概率。在盈利平衡点(纯利润为0),通过施药获得净利润的概率变幅在0.328～0.998之间;如果要获得1 500元/hm~2的净利润,各施药处理概率的变幅为0.024～0.993,其中40%氯虫苯甲酰胺·噻虫嗪WG+18.7%丙环唑·嘧菌酯SE处理的盈利概率最高(0.986～0.993),其次18.7%丙环唑·嘧菌酯SE和40%氯虫苯甲酰胺·噻虫嗪WG+17%吡唑醚菌酯·氟环唑SE处理的盈利概率也超过0.947。本研究表明40%氯虫苯甲酰胺·噻虫嗪WG+18.7%丙环唑·嘧菌酯SE是防治当地玉米病虫害理想的杀虫剂杀菌剂施药组合。 相似文献
15.
ABSTRACT The selective effect of quantitative host resistance on pathogen aggressiveness is poorly understood. Because two previous experiments with a small number of bread wheat cultivars and isolates of Mycosphaerella graminicola had indicated that more susceptible hosts selected for more aggressive isolates, we conducted a larger experiment to test that hypothesis. In each of 2 years, six cultivars differing in their levels of partial resistance were planted in field plots, and isolates were collected from each cultivar early and late in the growing season. The isolates were inoculated as populations bulked by cultivar of origin, field replicate, and collection date on seedlings of the same six cultivars in the greenhouse. The selective impact of a cultivar on aggressiveness was measured as the difference in aggressiveness between early and late isolates from that cultivar. Regression of those differences on disease severity in the field yielded significance values of 0.0531 and 0.0037 for the 2 years, with moderately resistant cultivars selecting for more aggressive isolates. In a related experiment, the protectant fungicide chlorothalonil was applied to plots of two susceptible cultivars to retard epidemic development. When tested in the greenhouse, isolates of M. graminicola from those plots were significantly more aggressive than isolates from the same cultivars unprotected by fungicide. 相似文献
16.
ABSTRACT Leaf rust uredospore production and lesion size were measured on flag leaves of adult wheat plants in a glasshouse for different lesion densities. We estimated the spore weight produced per square centimeter of infected leaf, per lesion, and per unit of sporulating area. Three levels of fertilization were applied to the plants to obtain different nitrogen content for the inoculated leaves. In a fourth treatment, we evaluated the effect of Septoria tritici blotch on leaf rust uredospore production. The nitrogen and carbon content of the spores was unaffected or marginally affected by lesion density, host leaf nitrogen content, or the presence of Mycosphaerella graminicola on the same leaf. In leaves with a low-nitrogen content, spore production per lesion was reduced, but lesion size was unaffected. A threshold effect of leaf nitrogen content in spore production was however, evident, since production was similar in the medium- and high-fertilizer treatments. In leaves inoculated with M. graminicola and Puccinia triticina, the rust lesions were smaller and produced fewer spores. The relationships among rust lesion density, lesion size, and uredospore production were fitted to a model. We determined that the density effect on spore production resulted mainly from a reduction in lesion size, the spore production per unit of sporulating surface being largely independent of lesion density. These results are consistent with those obtained previously on wheat seedlings. The main difference was that the sporulation period lasted longer in adult leaves. 相似文献
17.
为筛选适用于小麦叶锈病防治的化学药剂,本研究选取吡唑醚菌酯和氟环唑及二者不同比例复配组合,采用喷雾接种法,测定了吡唑醚菌酯和氟环唑单剂及其不同复配比例在作为保护剂使用时对小麦叶锈病的室内防治效果,并测定了室内筛选确定的最佳比例复配药剂对小麦的安全性及对小麦叶锈病的田间防治效果。室内防效试验显示：吡唑醚菌酯、氟环唑及二者不同比例复配对小麦叶锈病病斑扩展有强烈的抑制作用,其中吡唑醚菌酯的抑制作用更强,其EC50值为0.01μg/mL。联合毒力评价表明：所有复配组合均表现出协同相加作用,吡唑醚菌酯·氟环唑质量比50∶133复配时增效系数(SR)最大,为1.50。室内及田间防治试验表明：在所设浓度梯度范围内,防效与浓度呈正相关;在有效成分120 g/hm2剂量下,26%吡唑醚菌酯·氟环唑悬浮剂(SC)的田间防效为85.12%,优于各自单剂处理。安全性评价结果显示：所有处理均能保证不同品种小麦正常生长,未发生药害现象。研究表明,吡唑醚菌酯·氟环唑复配对小麦叶锈病有很好的防治效果,可为生产上防治小麦叶锈病和科学用药提供理论依据。 相似文献
18.
Sugar beet is a major crop in Morocco and Cercospora leaf spot is one of its most important fungal diseases. In Morocco, thiophanate methyl (benzimidazole) and difenoconazole (demethylation inhibitor, DMI) have been used extensively in the management of Cercospora leaf spot. In this study, samples of Cercospora beticola Sacc were collected from four major production areas. The identification of all isolates was confirmed using a PCR test with specific primers. Radial mycelia growth of each isolate in unmodified potato dextrose agar medium was compared to mycelia growth in the same medium modified with thiophanate methyl (1, 5, 10 and 50 ppm) or the DMIs difenoconazole, epoxiconazole and tetraconazole (0.1, 0.5, 1, 5, 10 and 50 ppm) or the quinone outside inhibitors (QOIs) azoxystrobin and trifloxystrobin (1, 5, 10 and 50 ppm). The percentage of inhibition obtained was used for the half maximal effective concentration (EC50) calculation. All the isolates showed resistance to the thiophanate methyl molecule to different degrees. Three groups were identified: low resistance with EC50 less than 100 ppm, moderate resistance with EC50 between 100 and 1000 ppm, and very resistant with EC50 more than 1000 ppm. For difenoconazole, 41% of isolates were sensitive (EC50 < 0.05 ppm) and 59% were resistant, while for tetraconazole and epoxiconazole 6% were sensitive (EC50 < 0.01 ppm), 66.7 % had medium resistance (0.01 < EC50 < 1 ppm) and 27.3% were resistant (EC50 > 1 ppm). For QOIs, azoxystrobin was less effective for mycelial inhibition than trifloxystrobin, with 54.5% of isolates with resistance to azoxystrobin (EC50 > 100 ppm). 相似文献
19.
Jean Sanssené Sameh Selim Céline Roisin‐Fichter Lynda Djerroud Caroline Deweer Patrice Halama 《Pest management science》2011,67(9):1134-1140
BACKGROUND: Septoria leaf blotch is the most important disease of wheat in Europe. To control this disease, fungicides of the 14α‐demethylase inhibitor group (DMIs) have been widely used for more than 20 years. However, resistance towards DMIs has increased rather quickly in recent years. The objective of this study was to evaluate, on plants and under controlled conditions, the protective and curative efficacy of the DMI fungicide prothioconazole against three current isolates of M. graminicola, chosen to belong to different DMI‐resistant phenotypes. Fungicide efficacy was assessed by visual symptoms and by quantitative real‐time polymerase chain reaction (PCR). RESULTS: With a protective fungicide application, prothioconazole was always effective against each isolate. This was in accordance with the EC50 results. However, curative efficacy differed between the isolates. It remained at a good level, between 60 and 70% against one isolate, whereas it was strongly affected by late applications from 7 days post‐inoculation with the two other isolates. CONCLUSION: A protective application of prothioconazole in wheat crops could be the best strategy to keep a high efficacy against Septoria leaf blotch. Copyright © 2011 Society of Chemical Industry 相似文献
20.
J. Sudisha 《Pesticide biochemistry and physiology》2005,81(3):188-197
Three commercial formulations of strobilurins, viz., azoxystrobin, kresoxim-methyl, and trifloxystrobin were evaluated for their efficacy against pearl millet downy mildew disease caused by Sclerospora graminicola. In vitro studies revealed inhibition of S. graminicola sporulation, zoospore release, and zoospore motility at 0.1-2 μg ml−1 of all the three fungicides. The fungicides were evaluated for phytotoxic effects on seed quality parameters and for their effectiveness against downy mildew disease by treating pearl millet by: (1) seed dressing, (2) seed dressing followed by foliar spray, and (3) also by foliar spray alone. The highest non-phytotoxic concentrations of 5, 10, and 10 μg ml−1 for azoxystrobin, trifloxystrobin, and kresoxim-methyl, respectively, were selected for further studies. Under greenhouse conditions, these fungicides showed varying degrees of protection against downy mildew disease. Among the three fungicides, azoxystrobin proved to be the best by offering disease protection of 66%. Further, seed treatment along with foliar application of these fungicides to diseased plants showed enhanced protection against the disease to 93, 82, and 62% in treatments of azoxystrobin, kresoxim-methyl and trifloxystrobin respectively. Foliar spray alone provided significant increase in disease protection levels of 91, 79, and 59% in treatments of azoxystrobin, kresoxim-methyl, and trifloxystrobin, respectively. Disease curative activity of azoxystrobin was higher compared to trifloxystrobin and kresoxim-methyl. Tested fungicides showed weaker translaminar activity, as the disease inhibition was marginal when applied on adaxial leaf surface. Partial systemic activity of azoxystrobin was evident by root uptake, while trifloxystrobin and kresoxim-methyl showed lack of systemic action in pearl millet. A trend in protection against downy mildew disease similar to greenhouse results was evident in the field trials. Grain yield was significantly increased in all strobilurin fungicide treatments over control and maximum increase in yield of 1673 kg ha−1 was observed in combination treatments of seed treatment and foliar spray with azoxystrobin. 相似文献