三化螟防治效果的变化高明昌（安微省芜湖病虫测报中心站２４１００２）本文根据历年测报资料汇编中三化螟多年第二～三代田间卵块密度和螟害率数据，提出以卵块密度与对应防治后螟害率间的比值变化，表达防治效果的相对变化。定义：百卵螟害率＝防治后螟害率（％）÷每亩... Based on data from previous surveys, the data of egg mass densities and stem borers of the third to third generations of BELs were screened in this paper. Based on the data of egg mass densities Corresponding to the post-control rate of the damage between the borer, the relative change in the prevention and control effect. Definition: Hundred egg damage rate = pest control rate (%) ÷ per acre