Table3_Seed Treatment with Diamide and Neonicotinoid Mixtures for Controlling Fall Armyworm on Corn: Toxicity Evaluation, Effects on Plant Growth and Residuality.DOC

The diamides, chlorantraniliprole (CHL) and cyantraniliprole (CYA), have been used as seed treatment agents against the fall armyworm (FAW), Spodoptera frugiperda in China. However, large-scale application of these two insecticides is prohibited because of their high cost. The neonicotinoid insecticides, clothianidin (CLO) and thiamethoxam (THI), are cheaper and widely used. In this study, we tested the efficacy of CHL + CLO and CYA + THI as seed treatment agents against FAW larvae both in laboratory and field conditions. Laboratory experiments showed that the two binary mixtures (both 240 g.a.i.100 kg−1 corn seeds) caused FAW mortality exceeded 84.00% at 14 days after seedling emergence (DAE). The mortality of the binary mixtures were similar to either CHL (300 g.a.i.100 kg−1corn seeds) or CYA (144 g a.i.100 kg−1corn seeds), but higher than CLO (120 g.a.i.100 Kg−1corn seeds) or THI (180 g a.i.100 kg−1corn seeds). Two independent field experiments showed that both binary mixtures resulted in above 68.00% control efficacy at 14 DAE, suggesting that these insecticidal combinations could effectively control FAW over a relative long period. In addition, both binary mixtures showed no negative effects on the growth and development of corn seedlings. The residues of binary mixtures in corn leave were also lower at 28 DAE as compared to residues in CHL or CYA alone. Most importantly, the costs of CHL + CLO were reduced up to 50% and CYA + THI up to 20% when compared to singly used chemical. Totally, our results indicated that CHL + CLO and CYA + THI had the same control efficacy as CHL or CYA alone, but with much lower cost.

二酰胺类杀虫剂（diamides）氯虫苯甲酰胺（chlorantraniliprole, CHL）与氰虫酰胺（cyantraniliprole, CYA）曾在我国作为种子处理剂，用于防控草地贪夜蛾（fall armyworm, FAW，学名：Spodoptera frugiperda）。但因二者成本高昂，无法实现大规模推广应用。新烟碱类杀虫剂（neonicotinoid insecticides）噻虫胺（clothianidin, CLO）与噻虫嗪（thiamethoxam, THI）成本更低，应用范围更为广泛。本研究针对CHL+CLO与CYA+THI两种二元复配药剂，在室内与田间条件下评价其对草地贪夜蛾幼虫的防治效果。室内试验结果表明，两种二元复配药剂（均按每100 kg玉米种子添加240 g有效成分（g.a.i.）的剂量施用）在玉米出苗后14天（days after emergence, DAE）时，对草地贪夜蛾幼虫的死亡率均超过84.00%。该二元复配药剂的防治效果与单剂CHL（每100 kg玉米种子添加300 g有效成分）或CYA（每100 kg玉米种子添加144 g有效成分）相当，但显著高于单剂CLO（每100 kg玉米种子添加120 g有效成分）或THI（每100 kg玉米种子添加180 g有效成分）。两项独立田间试验结果显示，两种二元复配药剂在玉米出苗后14天时的防治效果均达68.00%以上，表明该杀虫复配组合可在较长周期内有效防控草地贪夜蛾。此外，两种二元复配药剂对玉米幼苗的生长发育无不良影响。与单剂CHL或CYA相比，两种二元复配药剂在玉米叶片中的残留量在出苗后28天时更低。最为关键的是，与单剂施用相比，CHL+CLO的成本可降低50%，CYA+THI的成本可降低20%。综上，本研究结果表明，CHL+CLO与CYA+THI的防治效果与单剂CHL或CYA相当，但成本显著降低。