Contact Activity of Methomyl, Acephate, Dichlorvos and Trichlorfon to Tobacco Beetle Larva Effect of Acephate triadimefon Ultra fine Dust Seed coating Agent on Control of Disease and Pests of Wheat and Maize in Earlier Stage of Growing Period 几种杀虫剂对烟草甲幼虫的触杀毒力乙福酮超微粉体种衣剂对小麦和玉米前期病虫害防治效果的研究