一发生概况近年来,随着双、三熟制的变革、种植大面积杂交水稻和天敌因素的变化,三种螟虫的发生量:三化螟持续偏多,大螟时起时伏,二化螟迅速回升。目前,除三化螟仍然存在较大威胁外,二化螟已上升为重要害虫,主要表现在两个方面。(一)发生范围越来越大江苏省的二化螟过去只有太湖流域和苏北部份地区发生比较严重,但近两年来,苏州、扬州、镇江、盐城等四个地区普遍大发生,在局部地区,对水稻的威胁已超过三化螟。如扬州地区:现在除里下河地区连续大发生外,丘陵山区、沿江、沿运地区发生都很严重。1979 In recent years, with the double and triple cropping changes, planting large areas of hybrid rice and natural enemies of factors, the occurrence of three kinds of stem borer: Stem Borer continued more than when the Sesamia inability, two Borer quickly picked up. At present, except the three stem borer is still a greater threat, the stem borer has risen to an important pest, mainly in two aspects. (A) the occurrence of a growing range In the past, only the Taihe River Basin in Jiangsu Province and parts of northern Jiangsu occurred more serious, but the past two years, Suzhou, Yangzhou, Zhenjiang, Yancheng and other four areas generally occur in In some areas, the threat to rice has surpassed the yellow rice borer. Such as Yangzhou: Now except Lixiahe continuous large area occurs, the hilly area, along the river, along the transport area are very serious. 1979