几种杀菌剂对莴苣霜霉病的田间防治效果评价

霜霉病是莴苣生产上的主要病害.为推荐安全高效的莴苣霜霉病防治药剂,开展了500 g/L氟啶胺悬浮剂、75％百菌清可湿性粉剂、722 g/L普力克(霜霉威盐酸盐)水剂等3种杀菌剂防治莴苣霜霉病的田间药效试验.结果 表明,3种供试药剂在试验剂量范围内均表现出较好的防治效果,对供试作物安全,可作为田间防治莴苣霜霉病的推荐药剂...     

5种杀菌剂对葡萄霜霉病的田间防治效果

为了筛选防治葡萄霜霉病的高效、低毒杀菌剂,选择了10％氟噻唑吡乙酮可分散油悬浮剂、80％代森锰锌可湿性粉剂、50％吡唑醚菌酯水分散粒剂、25％氰霜唑可湿性粉剂、25％烯酰吗啉悬浮剂5种杀菌剂开展田间防效试验.结果 表明,参试药剂中,10％氟噻唑吡乙酮可分散油悬浮剂防效最好,3次喷施后,对葡萄霜霉病的防效为95.79％,...     

4种药剂对北京地区葡萄霜霉病的防效

北京地区葡萄霜霉病的抗药性较为严重,为筛选能有效防治该病的低毒农药,选择了4种药剂:60％唑醚·代森联水分散粒剂、68.75％噁酮·锰锌水分散粒剂、10％氟噻唑吡乙酮可分散油悬浮剂、23.4％双炔酰菌胺悬浮剂在北京通州开展了田间施药防病试验.结果表明,氟噻唑吡乙酮对葡萄霜霉病的防效较高、持效期长、效益好,推荐在生产中将...     

6种杀菌剂防治黄瓜霜霉病的田间药效评价

[目的]霜霉病是黄瓜的重要病害之一,严重影响其产量.通过试验,进行啶氧菌酯、氰霜唑等杀菌剂对防治黄瓜霜霉病的防控效果对比.[方法]利用喷雾法测定6种药剂对黄瓜霜霉病的防治效果.[结果]6种供试药剂的防效由高到低依次为氟噻唑吡乙酮10％OD、氟菌·霜霉威687.5 g/L SC、吡唑醚菌酯25％EC、氰霜唑100 g/L SC、烯酰吗啉50％WP、啶氧菌酯22.5％SC.[结论]10％氟噻唑吡乙酮可分散油悬浮剂对黄瓜霜霉病有优异的防治效果,末次药后7 d平均防效达84.13％,末次药后14 d平均防效仍为79.21％,且对黄瓜安全无药害,可作为防治黄瓜霜霉病的首选药剂.除22.5％啶氧菌酯水悬浮剂和50％烯酰吗啉可湿性粉剂外的其他几种药剂亦可作为防治黄瓜霜霉病的推荐药剂交替使用.     

3种杀菌剂防治黄瓜白粉病的田间防效

选用3种杀菌剂进行黄瓜白粉病田间防治试验.发现42.8％氟菌·肟菌酯SC对黄瓜白粉病具有较好的防治效果,制剂用量为14 mL/667m2的处理对黄瓜白粉病的防效显著高于75％肟菌·戊唑醇WG 13.3 g/667m2和30％醚菌·啶酰菌SC 25.8 mL/667m2的防效,并且对黄瓜生长发育无不良影响.     

8种杀菌剂对茉莉花白绢病的田间防效

为筛选出能够有效防治茉莉花白绢病的药剂,探索适宜的防治方法,选用8种杀菌剂对茉莉花白绢病进行了田间防治试验。结果表明,第3次药后14 d,50%啶酰菌胺水分散粒剂、250 g/L吡唑醚菌酯乳油和430 g/L戊唑醇悬浮剂对茉莉花白绢病的病指防效分别为88.28%、87.65%和83.10%,持效期较长;40%菌核净可湿性粉剂、15%三唑酮可湿性粉剂、50%腐霉利可湿性粉剂、1亿CFU/g哈茨木霉菌水分散粒剂防效一般,持效期较短;6%井冈·240亿个/g枯芽菌可湿性粉剂对茉莉花白绢病无明显防治效果。推荐在病害易发期选用防效较好的药剂先进行土壤处理,再采用茎叶喷雾的方式连续施药2~3次防治该病害。     

7种进口杀菌剂对“紫秋”刺葡萄霜霉病的田间防治效果初探

选用25%吡唑醚菌酯EC、250 g/L嘧菌酯SC、52.5 g/L噁酮·霜脲氰WG、68.75 g/L氟吡菌胺·霜霉威SC、66.8%丙森·缬霉威WP、50%烯酰吗啉WP和50%醚菌酯WG等7种杀菌剂,进行了"紫秋"刺葡萄霜霉病的田间药效防控试验。试验结果表明,7种药剂对"紫秋"刺葡萄霜霉病都有稳定的防治效果,其中25%吡唑醚菌酯EC 1 500倍液、250g/L嘧菌酯SC 1 000倍液、52.5 g/L噁酮·霜脲氰WG 2 000倍液、68.75 g/L氟吡菌胺·霜霉威SC 800倍液、66.8%丙森·缬霉威WP 500倍液、50%烯酰吗啉WP 3 000倍液,平均防效都在80%以上。建议生产上应用25%吡唑醚菌酯EC 1 500倍液、250 g/L嘧菌酯SC 1 000倍液、52.5 g/L噁酮·霜脲氰WG 2 000倍液、68.75 g/L氟吡菌胺·霜霉威SC 800倍液、66.8%丙森·缬霉威WP 500倍液或50%烯酰吗啉WP 3 000倍液等6种药剂防治葡萄霜霉病,在发病初期开始用药,间隔10 d喷施1次,连喷3～4次,即可控制葡萄霜霉病的蔓延。     

8种杀菌剂防治葡萄霜霉病田间药效试验

比较了8种杀菌剂对葡萄霜霉病的防治效果。结果表明:烯酰吗啉.甲霜灵30%水分散粒剂600倍液、烯酰吗啉40%悬浮剂600倍液、甲霜.锰锌72%水分散粒剂400倍液、嘧菌酯25%悬浮剂1 500倍液以及氯化十二烷基苄基铵10%水剂1 000倍液对葡萄霜霉病的防治效果良好,显著优于传统药剂三乙膦酸铝80%水分散粒剂500倍液、代森锰锌80%可湿性粉剂800倍液、丙森锌70%可湿性粉剂400倍液。其中,烯酰吗啉.甲霜灵30%水分散粒剂600倍液效果尤佳。     

几种杀菌剂对小麦纹枯病的室内毒力和田间防效

室内采用菌落生长速率法测定了适乐时、烯唑醇、甲基立枯磷、敌力脱、多菌灵和三唑酮等杀菌剂对小麦纹枯病菌的毒力 ,各药剂的EC50 值分别为 :0.030、0.082、0.205、0.224、1.814、1.971、2.065μg/mL。在田间适乐时 (2g/100kg种子)拌种的防治效果为75.2% ,其余各试验药剂喷雾的防治效果为 :烯唑醇 (6.3g/667m2)72.6% ,敌力脱 (5g/667m2)65.5% ,甲基立枯磷 (50g/667m2)61.3% ,多菌灵 (50g/667m2)49.7% ,井冈霉素(10g/667m2)56.3% ,三唑酮 (8.8g/667m2)60.4%。     

8种杀菌剂不同浓度处理对小麦白粉病的田间防效

为筛选防治小麦白粉病的高效杀菌剂,研究了6%寡糖·链蛋白可湿性粉剂、10%氟硅唑微乳剂、20%丙环唑微乳剂、25%腈菌唑乳油、10%苯醚甲环唑微乳剂、25%嘧菌酯悬浮剂、62.25%锰锌·腈菌唑可湿性粉剂、25%三唑酮可湿性粉剂各自高、中、低浓度处理对河南新乡小麦白粉病的田间防效。整体上三唑酮对小麦白粉菌群体仍具较好防控效果。试验中该药剂处理也获得了最高的经济效益(产出/投入);锰锌·腈菌唑与腈菌唑的防效无明显差异,均低于其他药剂;而其他6种杀菌剂防效无明显差异。寡糖·链蛋白和三唑酮的高、低浓度处理药效呈显著差异,氟硅唑的高、中浓度处理药效均显著高于其低浓度处理,锰锌·腈菌唑高、中、低三浓度间防效呈显著性差异。产量分析显示,三唑酮处理区产量最高。     

Comparative efficacy of strobilurin fungicides against downy mildew disease of pearl millet

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.     

两种候选甲氧基丙烯酸酯类杀菌剂对黄瓜霜霉病的作用方式

20%唑胺菌酯EC、20%SYP-3998 SC是甲氧基丙烯酸酯类候选杀菌剂,为探索两药剂对黄瓜霜霉病的作用方式,采用盆栽植株喷雾-叶碟法、叶碟喷雾法、盆栽植株喷雾-叶碟法分别测定两药剂对黄瓜霜霉病的保护、治疗及持效期,并采用离体叶片法、叶碟法测定二者对黄瓜霜霉病的铲除作用.结果表明:20%唑胺菌酯EC和20%SYP-3998 SC具有良好的保护、治疗及铲除作用.两药剂的铲除作用表现在能抑制黄瓜霜霉病菌病斑扩展、孢子囊产生及孢子囊再侵染,与孢子囊混合接种能显著降低孢子囊的致病性.此外,20%唑胺茵酯EC和20%SYP-3998 SC具有7～10天的持效期;20%唑胺茵酯EC预防、治疗、铲除效果及持效性均优于20%SYP-3998 SC及对照药剂25%嘧菌酯SC.     

25%嘧菌酯悬浮剂防治黄瓜霜霉病药效试验

黄瓜霜霉病是黄瓜最主要病害之一,近年来我市的黄瓜霜霉病日趋严重,已成为黄瓜种植过程中的一个重要障碍。为了更有效地防治黄瓜霜霉病,我们进行了本试验,现将试验结果报告如下。     

不同助剂提高烯酰吗啉防治莴苣霜霉病的效果研究

为研究不同喷雾助剂提高烯酰吗啉防治莴苣霜霉病的效果,采用喷雾法测定了有机硅助剂Silwet 408、阴离子表面活性剂捷成、植物源助剂克欧森和怀农特4种助剂对50％ 烯酰吗啉可湿性粉剂在莴苣上的沉积率及对霜霉病防治效果的影响.烯酰吗啉不添加助剂以及分别添加4种助剂后,第1次施药后1 d在莴苣植株内的沉积量分别为4.10、...     

Occurrence in Italy and characteristics of lettuce downy mildew (Bremia lactucae) resistant to phenylamide fungicides

Control of lettuce downy mildew (Bremia lactucae) with phenylamide fungicides has failed in some intensive lettuce-producing areas in Northern Italy since Spring 1993. Before then, these chemicals and particularly metalaxyl, provided the best disease control. The sensitivity of Bremia lactucae isolates collected in such areas to metalaxyl was evaluated in the laboratory. These strains grew and sporulated profusely on lettuce seedlings treated with 100 and 200 ppm of metalaxyl, whereas sensitive control strains were completely inhibited when treated with fungicide concentrations ranging from 0.5–1 ppm. Thus in Italy occurrence of resistance to phenylamide fungicides in Bremia lactucae has also been demonstrated, as in almost all the countries where these chemicals were previously authorised. Subsequently, a demonstration of occurrence of resistance was made and the virulence pattern of several strains (resistant and sensitive to metalaxyl) was characterised using differential NL series containing the 13 DM resistant genes or R factors. The results suggest the occurrence of a new pathotype in Italy different from all the 16 NL Bremia lactucae races studied.     

Silicon and increased electrical conductivity reduce downy mildew of soilless grown lettuce

Downy mildew of lettuce, caused by Bremia lactucae, is difficult to control in soilless systems by using conventional methods of disease management because few chemicals are registered, while resistant cultivars face the problem of resistance break down; therefore other methods for disease control need to be investigated. The effect of silicon salt as well as increased electrical conductivities against downy mildew was evaluated in four experiments carried out in hydroponically systems, using the cultivar of lettuce “Cobham Green”, known for its susceptibility to the pathogen. Silicon, as potassium silicate, was added at 100 mg l⁻¹ of nutrient solution at three levels of electrical conductivity: 1.5–1.6 mS cm⁻¹ (EC1), 3.0–3.5 mScm⁻¹ (EC2, 0.70 g l⁻¹ NaCl) and 4.0–4.5 mS cm⁻¹ (EC3, 0.95 g l⁻¹ NaCl) respectively. Lettuce plants, grown for 14–20 (trials 1 and 2) and 36–45 (trials 3 and 4) days in the different nutrient solutions tested, were inoculated with B. lactucae conidia with a maximum of two inoculations before final disease assessment carried out 14–21 days after the inoculation able to give symptoms. EC and potassium silicate significantly influenced downy mildew incidence and severity, while their interaction was not a significant factor. The addition to the standard nutrient solution (EC1) of potassium silicate resulted in a significant reduction of downy mildew severity in trials 1 and 2 where plants were artificially inoculated 15 and 20 days after transplanting. This efficacy was slight on plants grown for 36 and 45 days before inoculation in a soil drenched with EC1 amended with potassium silicate. EC2 gave a significantly similar downy mildew reduction than EC2 added with potassium silicate in trial 3. Plants grown for 36 and 45 days at the highest electrical conductivity (EC3) showed a significant reduction in severity of downy mildew compared with that observed at EC2 level. The best results, in terms of disease control, were given by the addition of potassium silicate to the EC3 solution. This combination also led to a significantly increased plant biomass. The possibility and benefits of applying potassium silicate and increased EC amendments in practice is discussed.     

Spatial analysis of lettuce downy mildew using geostatistics and geographic information systems

ABSTRACT The epidemiology of lettuce downy mildew has been investigated extensively in coastal California. However, the spatial patterns of the disease and the distance that Bremia lactucae spores can be transported have not been determined. During 1995 to 1998, we conducted several field- and valley-scale surveys to determine spatial patterns of this disease in the Salinas valley. Geostatistical analyses of the survey data at both scales showed that the influence range of downy mildew incidence at one location on incidence at other locations was between 80 and 3,000 m. A linear relationship was detected between semivariance and lag distance at the field scale, although no single statistical model could fit the semi-variograms at the valley scale. Spatial interpolation by the inverse distance weighting method with a power of 2 resulted in plausible estimates of incidence throughout the valley. Cluster analysis in geographic information systems on the interpolated disease incidence from different dates demonstrated that the Salinas valley could be divided into two areas, north and south of Salinas City, with high and low disease pressure, respectively. Seasonal and spatial trends along the valley suggested that the distinction between the downy mildew conducive and nonconducive areas might be determined by environmental factors.     

Efficacy of different fungicides against the leaf spot of lettuce caused by Allophoma tropica

Journal of Plant Diseases and Protection - The efficacy of different fungicides, belonging to different chemical groups, was in vitro and in vivo tested in glasshouse trials against Allophoma...     

The occurrence, characteristics and distribution in the United Kingdom of resistance to phenylamide fungicides in Bremia lactucae (lettuce downy mildew)

Failure to control Bremia lactucae (lettuce downy mildew) with metalaxyl in an intensive lettuce-producing region of Lancashire at the end of 1983 was shown to be due to the occurrence of a high level of resistance to this fungicide (isolates capable of growth at < 100 μg/ml metalaxyl). During most of 1984, metalaxyl-resistant isolates were obtained from numerous sites but all within a 20-km radius of the initial outbreak. Thereafter, at the end of 1984 and during 1985, metalaxyl-resistant isolates were recovered from most major lettuce-producing regions in the UK with protected crops more affected than field crops. AH metalaxyl-resistant isolates tested were identical in their response to fungicide, sexual compatibility type (B2) and virulence phenotype, probably representing a clone from a single origin. The resistant pathotype was virulent on resistance factors R 1-10 and 12-15 but lacked virulence for R 11 and 16-18. This was also the most common virulence phenotype among sensitive isolates collected at the same time. Cross-resistance to other phenylamide fungicides was demonstrated but isolates resistant and sensitive to phenylamide showed a similar response to the unrelated systemic fungicides propamocarb and fosetyl-Al. An F₁ sexual progeny isolate from a cross between a phenylamide-sensitive and a phenylamide-resistant isolate (presumed heterozygous at the locus or loci regulating response to phenylamide fungicides) exhibited an intermediate response to phenylamide fungicides. No isolates of this type were obtained from the field. At the high concentrations affecting spore germination, phenylamide fungicides exhibited lower activity against a resistant isolate compared with a sensitive isolate. The findings are discussed in relation to future control strategies, the population biology of the fungus and possible directions for lettuce breeding programmes.     

Further characterization of field resistance in lettuce to Bremia lactucae (downy mildew)

The development of five Bremia lactucae isolates on the field-resistant crisphead lettuce cultivar Iceberg was compared under field conditions with that on the more susceptible crisphead cultivar Ithaca. With each of five isolates, the epidemic developed more rapidly on Ithaca than Iceberg; lesions on Ithaca were more numerous, larger and sporulated more profusely than on Iceberg. There was no evidence for adaptation of isolates to Iceberg, which provides some additional evidence that the resistance of this cultivar could be non-differential (horizontal). There was, however, evidence of non-specific differences between isolates in their quantitative virulence.