我区自1985年以来,三化螟为害面积逐年扩大,为害程度越来越重。全年发生三代,以第三代危害最重,损失产量最大。1987年第三代三化螟的螟害率一般田块达1.5—2.6%,严重田块高达15%以上。要控制三代三化螟的危害,重点是拆除三代的“桥梁田”,在连作稻地区,其主要虫源田是连晚秧田。据1988年统计,重螟地区的双林、南浔、织里、升山、常 Since 1985, our district has been increasing the damage area of ​​Borer once and for all due to its damage. Three generations occur throughout the year, the third generation of the most damaging, the largest loss of output. In 1987 the third generation of Borer borer rate generally 1.5-2.6% field plots, severe field up to 15% or more. To control the harm of the three generations of Borer, the focus is to dismantle the “bridge fields” of the three generations. In the continuous cropping rice area, the main source of insect pests is the late seedling. According to statistics in 1988, the heavy borer boreal Shuanglin, Nanxun, weaving, or Hill, often