取食草坪的斜纹夜蛾生物学及药剂敏感性研究

Studies on biology of Spodoptera litura (Fabricius) on lawn and its susceptibility to pesticide

1龄斜纹夜蛾[Spodopteralitura(Fabricius)]幼虫可以取食阔叶草坪草白三叶和马蹄金,但拒食禾本科草坪草高羊茅和狗牙根。不同的取食对象导致斜纹夜蛾的生物学特性和对杀虫剂的敏感性的差异。取食草坪草白三叶及马蹄金的斜纹夜蛾与取食甘蓝的斜纹夜蛾比较,幼虫的历期分别减少3.77,3.61d,但其它虫期并无显著差异。同时对杀虫剂的敏感性增加,以毒死蜱为例,取食白三叶及马蹄金的斜纹夜蛾其LC50分别为15.3,19.0mg/L,而取食甘蓝的LC50则为29.4mg/L,对4种不同杀虫剂的敏感性,以氟铃脲最高,其次为毒死蜱、锐劲特、杀灭菊酯。结果表明,在草坪的斜纹夜蛾成虫活动量低于甘蓝等蔬菜地。相对于甘蓝,白三叶和马蹄金草坪草更不适合作为斜纹夜蛾的寄主。

The first instar larvae of Tobacco cutworm, Spodoptera litura(Fabricius) grow on broad-leaf turfgrass, but will die on grassy turfgrass. The insect feeding on different plants shows various biological characteristics and susceptibility to pesticides. The larval duration of S.litura(Fabricius) on turfgrass Trifolium repens L.and Dichondra repens Forst is shorter than it on the cabbage by 3.77 days and 3.61 days,respectiviy,although there is no difference in stages of egg, pupae and adult. Besides, the larvae on turfgrass T.repens L and D.repens Forst are more sensitive to pesticide than that on the cabbage. Take chlorpyrifos for example, the LC_(50) of S.litura(Fabricius) on turfgrass T.repens L and D.repens Forst is 15.3 mg/L and 19.0 mg/L respectively, while the LC_(50) of the pest on the cabbage is 29.4 mg/L. Hexafluron is the most toxic to the pest, followed by chlorpyrifos, fipronil , and fenvalerate. The number of adults on lawns attracted by sex hormone is less than that on the cabbage. Therefore, T.repens and D.repens turfgrass are not as good diets as the cabbage for the pest.