虫螨腈对草地贪夜蛾幼虫的室内毒力及田间防效

Toxicity and field control efficacy of chlorfenapyr on the larvae of Spodoptera frugiperda

草地贪夜蛾Spodoptera frugiperda(J.E.Smith),是一种广泛存在于美洲的杂食性农业害虫。据报道2019年1月草地贪夜蛾入侵我国云南,截止2019年6月6日,已在全国18个省份的884个县(市、区)监测到发生为害,发生面积342万亩,已经对我国粮食安全造成重大威胁。在2019年5月,在广东省广州市花都区儒林村玉米田开展喷雾和喇叭口点施虫螨腈对草地贪夜蛾幼虫的防治试验以及室内毒力测定试验。试验结果表明,虫螨腈对草地贪夜蛾2龄幼虫具有良好的毒力活性;综合考虑在草地贪夜蛾1~3龄幼虫期,用药量67.5 g.a.i/hm^2、药液量675 L/hm^2常规喷雾效果更佳;在草地贪夜蛾4~6龄幼虫期,用药量22.5 g.a.i/hm^2、药液量225 L/hm^2喇叭口点施效果更佳,且喇叭口点施可以定位定向定量地直接到达草地贪夜蛾为害部位,可减少2/3的农药使用量,达到农药减量增效的目的。该研究结果为拟定草地贪夜蛾应急防控技术方案提供技术支撑和理论依据。

Spodoptera frugiperda(J.E.Smith)is an omnivorous agricultural pest widely distributed in America.It is reported that S.frugiperda has invaded Yunnan Province on Jan.,2019.As of June 6,2019,it has been detected in 884 counties(cities and districts)in 18 provinces of China,covering an area of 3.42 million mu,which has posed a major threat to food security in China.In May 2019,our research group had carried out control experiments on the larvae of S.frugiperda in maize field of Rulin Village,Huadu District,Guangzhou City,Guangdong Province,together with indoor toxicity determination,through spraying and flare opening application of chlorfenapyr.The results showed that chlorfenapyr had good indoor toxicity activity to the 2^nd instar larvae of S.frugiperda.To the 1^st^3^rd instar larvae,the effect of conventional spraying with the pesticide dosage of 67.5 g.a.i/hm^2 and the liquid dosage of 675 L/hm^2 was better than other treatments.When considering the 4^th^6^th instar larvae of S.frugiperda,spot application worked better with pesticide dosage of 22.5 g.a.i/hm^2 and liquid dosage of 225 L/hm^2.Flare opening application can directly reach the damage site of S.frugiperda and reduce 2/3 of the pesticide dosage,so as to achieve the purpose of reducing pesticide usage and increasing pesticide efficiency.Relevant research results has provided technical support and theoretical basis for developing the technical plan for emergency prevention and control of S.frugiperda.