防治玉米叶斑病高效药剂筛选及药剂减施增效技术

Screening of high effective fungicides for controlling maize leaf spot and the techonology for fungicide reduction and synergism

为有效防治玉米小斑病和弯孢叶斑病并减少化学农药使用量,本研究采用菌丝生长速率法从11种杀菌剂中选取抑菌效果较好的8种药剂进行田间小区药效试验。同时选取对两种叶部病害兼具防效的最佳药剂再与中量元素水溶肥、腐植酸、氨基寡糖素、芸苔素内酯等产品混配开展田间药效试验,确定该药剂田间施用浓度和增效组合。结果显示,各供试药剂对2种病菌菌丝生长具有不同的抑制作用,其中25%丙环唑EC、25%戊唑醇WP、40%氟硅唑EC、30%氟菌唑WP、12.5%烯唑醇WP在供试各浓度下对2种病菌抑制率均为100%,田间小区药效筛选测定中,25%戊唑醇WP防治效果最好,对玉米小斑病和弯孢叶斑病两种叶部病害防效分别为81.07%和72.22%。田间试验中,25%戊唑醇WP防治玉米小斑病和弯孢叶斑病的最佳施用浓度为2000倍液,防效分别为59.48%和53.96%。在减量50%情况下防效有所下降,配施氨基寡糖素后,防效可提高37.40百分点和22.98百分点,与最佳施用浓度防效相当,达到了减药增效的作用。

In order to effectively control Southern corn leaf blight and Curvularia leaf spot and reduce the use of chemical pesticides,eight fungicides with better inhibition effect were selected from 11 fungicides by mycelial growth rate method for field test.Meanwhile,the best fungicide for the two kinds of leaf diseases was mixed with medium elements,humic acid,amino-oligosaccharide,brassinolide and other products to determine the field application concentration and synergistic combination of the fungicide.The results showed that all the tested fungicides had different inhibitory effects on the mycelial growth of the two pathogens.The inhibition rates of propiconazol 25%EC,tebuconazole 25%WP,flusilazole 40%EC,triflumizole 30%WP and diniconazole 12.5%WP were all 100%at each tested concentration.Field trials demonstrated that tebuconazole 25%WP had the highest control effect with the efficacy of 81.07%and 72.22%on Southern corn leaf blight and Curvularia leaf spot,respectively.The optimum application concentration of tebuconazole 25%WP for Southern corn leaf blight and Curvularia leaf spot was 2000 times,and the control efficacies were 59.48%and 53.96%,respectively.The control effect decreased when the dosage was reduced by 50%,and the control efficacy was increased by 37.40 percentage points and 22.98 percentage points by the combined application of amino-oligosaccharide,which was equivalent to that at the optimum application concentration,achieving the effect of fungicide reduction and synergism.