烯肟菌胺与苯醚甲环唑对西瓜蔓枯病菌的联合毒力及防效

为明确烯肟菌胺与苯醚甲环唑不同比例混配对西瓜蔓枯病菌联合作用类型,采用含毒介质法测定了烯肟菌胺与苯醚甲环唑及其5 种配比对西瓜蔓枯病菌的毒力;并在田间测定了24%烯肟菌胺·苯醚甲环唑悬浮剂对西瓜蔓枯病防效。结果表明：烯肟菌胺与苯醚甲环唑及5:1、3:1、1:1、1:3 及1:5 混配对西瓜蔓枯病菌的EC50值分别是17.6、0.22、0.68、0.63、0.35、0.28、0.26 mg/L;共毒系数分别是182.70、134.63、124.16、104.33 和101.29。在西瓜蔓枯病发病初期连续喷施24%烯肟菌胺·苯醚甲环唑悬浮剂有较好防效,推荐剂量为200~400 mg/L。烯肟菌胺与苯醚甲环唑5:1、3:1 及1:1 配比对西瓜蔓枯病具有增效作用,1:3和1:5配比具有相加作用。24%烯肟菌胺·苯醚甲环唑悬浮剂可用于防治西瓜蔓枯病。     

苯醚甲环唑在土壤中的降解动力学及其影响因子

研究了苯醚甲环唑在北京、萧县、杭州及长沙4个地区土壤中的降解动力学,并探讨了土壤微生物、温度、含水量及药剂质量分数对其降解的影响.结果表明:苯醚甲环唑在4个地区土壤中的降解半衰期为11.63～21.77 d.土壤微生物对苯醚甲环唑降解起主导作用,灭菌土壤降解半衰期是非灭菌条件下的6.09倍;15～40℃范围内,温度升高,土壤中苯醚甲环唑降解加快,15～25℃降解速率增加幅度较大;士壤含水量过高(150%)和过低(25%)都不利于苯醚甲环唑降解,而土壤中药剂质量分数的增大对苯醚甲环唑降解则起阻碍作用.     

300g/L苯醚甲环唑·丙环唑乳油防治水稻纹枯病田间药效试验

对300g/L苯醚甲环唑·丙环唑EC防治水稻纹枯病的效果进行了田间药效试验,结果表明,300g/L苯醚甲环唑·丙环唑EC每公顷有效成分90g、120.15g的处理防治效果分别为84.80%,91.00%,比10%苯醚甲环唑EC、25%丙环唑EC提高12.91～19.11个百分点,比3%井冈霉素提高15.73～21.93个百分点。     

30％苯醚甲环唑·丙环唑EC对水稻纹枯病和稻曲病的田间防效

[目的]推广30％苯醚甲环唑·丙环唑EC.【方法]2008年在江苏省高淳县进行了田间药效试验,调查其对水稻纹枯病和稻曲病的防效。[结果]施药后各药剂均未对水稻产生药害。30％苯醚甲环唑·丙环唑EC225、300ml／hm2对水稻纹枯病的防效分别为93,36％、92．03％,差异不显著;对稻曲病防效分别为67,60％、81．71％,差异显著。其中,300ml／hm2处理的防效均显著高于对照药剂5％井冈霉素水剂4500ml／hm2。[结论]30％苯醚甲环唑·丙环唑EC安全性好、防效高。可推广示范,建议使用剂量300ml／hm2。     

Activities of azoxystrobin and difenoconazole against Alternaria alternata and their control efficacy

Tobacco brown spot caused by Alteraria alternata is a devastating disease of tobacco worldwide. In this study, we reported the effects of a strobilurin fungicide azoxystrobin and a sterol inhibitor difenoconazole on mycelial growth, spore germination, and control of brown spot. Both mycelial growth and spore germination bioassay results showed that sensitivity of A. alternata to difenoconazole was significantly lower than that to azoxystrobin. Azoxystrobin and the compound of azoxystrobin plus difenoconazole provided excellent control efficacy on tobacco brown spot in field. Disease control efficacies for three sprays of azoxystrobin at doses of 0.094, 0.19 and 0.28 Kg a.i./ha, of azoxystrobin plus difenoconazole at 0.15, 0.22 and 0.29 Kg a.i./ha, and of difenoconazole at 0.12 Kg a.i./ha were between 86.00% and 89.67%, between 86.14% and 89.23%, and between 55.14 and 58.41%, respectively. No phytotoxic symptoms were observed for the fungicides in field. These fungicides could potentially be used for brown spot control in tobacco.     

苯醚甲环唑·甲基硫菌灵65%可湿性粉剂高效液相色谱分析

采用高效液相色谱外标法,以甲醇-水作为流动相,用Hypersil BDS C18柱和紫外检测器,分析苯醚甲环唑.甲基硫菌灵复配制剂。结果表明：苯醚甲环唑和甲基硫菌灵的标准偏差分别为0.10和0.12;变异系数分别为0.39%和0.30%;平均回收率均为99.1%。     

几种药剂混配对黄瓜靶斑病的防治试验

为更加有效防治黄瓜靶斑病,开展几种药剂混配防治黄瓜靶斑病的田间药效试验。试验结果表明,供试药剂对黄瓜安全,对黄瓜生长发育无不良影响;从对黄瓜靶斑病的最终防治效果来看,4%四氟醚唑水乳剂+25%咪鲜胺水乳剂防效最好,为94.02%;其次为40%稻瘟灵可湿性粉剂+25%咪鲜胺水乳剂和10%苯醚甲环唑微乳剂+25%咪鲜胺水乳剂,二者防效都在90%以上。所以在生产实践中,建议用以上3种配方防治黄瓜靶斑病,以上全为制剂用量。     

30%多菌灵·多抗霉素可湿性粉剂防治苹果轮纹病田间药效试验

试验表明,30%多菌灵.多抗霉素可湿性粉剂以800～1000倍茎叶喷雾处理,对苹果轮纹病的防效显著,且对苹果（树）安全,应于苹果幼果期施药。     

300g/L苯醚甲环唑·丙环唑乳油对水稻纹枯病的田间防治效果研究

对300 g/L苯醚甲环唑.丙环唑EC防治水稻纹枯病进行田间药效试验,结果表明,300 g/L苯醚甲环唑.丙环唑EC有效成分90 g/hm2、112.5 g/hm2对水稻纹枯病的防治效果分别为85.48%、93.54%,比10%苯醚甲环唑EC 22.5 g/hm2处理分别提高8.15、16.21个百分点;比25%丙环唑EC 112.5 g/hm2处理分别提高15.66,23.72个百分点;比300 g/L苯醚甲环唑.丙环唑EC67.5 g/hm2处理分别提高19.29、27.35个百分点。300 g/L苯醚甲环唑.丙环唑EC防治水稻纹枯病的有效成分为90.0～112.5 g/hm2。     

Sensitivity to iprodione, difenoconazole and fludioxonil of Rhizoctonia cerealis isolates collected from wheat in China

Since the 1980s wheat sharp eyespot (WSE) caused mainly by Rhizoctonia cerealis has become one of serious diseases of wheat in China. In this study, the sensitivity of 89 R. cerealis isolates to different fungicides was evaluated using mycelial growth inhibition assays. The results showed that all R. cerealis isolates tested were sensitive to iprodione, difenoconazole and fludioxonil with mean EC₅₀ (effective concentration that results in 50% of mycelial growth inhibition) values of 0.419, 0.062 and 0.033 μg/ml, respectively. To evaluate the risk of fungicide resistance in R. cerealis, an attempt was made to induce resistant mutants in the laboratory. Although difenoconazole- and fludioxonil-resistant mutants were not obtained, we obtained seven independently iprodione-resistant (IR) mutants from 89 parental isolates. The EC₅₀ values for these IR mutants were greater than 100 μg/ml, whereas those for the original wild-type counterparts were less than 1 μg/ml. After having been subcultured on PDA for 10 generations, the IR mutants did not show any decrease in resistance to iprodione. Additionally, these IR mutants also showed resistance to fludioxonil but remained sensitive to difenoconazole. Osmotic sensitivity tests showed that the IR mutants were hypersensitive to osmotic stress generated by NaCl. Inoculation tests showed that all the IR mutants lost their ability to infect the host plant. Taken together, these results indicate that the current population of R. cerealis is sensitive to these fungicides and a fitness cost is associated with iprodione-resistant mutants of R. cerealis in both osmotic stress and pathogenicity. The information obtained in this study is useful in monitoring and managing fungicide resistance in R. cerealis populations in China.