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我省水稻螟害过去一直以三化螟为主,二化螟仅一代在部分深丘稻田造成为害。1977年以来,二化螟的发生数量逐年上升,为害程度渐超过三化螟。如成都市龙家区灯诱二化螟在三种螟虫中所占比例,由77年的13.5％上升到82年的68.5％。资中县田间虫口密度,由6.4％上升到75.3％。绵阳田间剥查的14,353被害株中,有螟虫8679头,二化螟占93.01％。新津、眉山、渠县、纳溪等地均属类似情况。据各地调查,在不防治的情况下,二化螟一代枯心率一般在5％左右,高的可达20％以上;二代可造成白穗、死孕穗
In our province, the rice stem borers have been dominated by the three rice stem borers. Only one generation of the rice borers causes damage in some deep-paddy rice fields. Since 1977, the occurrence of Chilo suppressalis increased year by year, the degree of damage more than Borer. For example, the percentage of lamppost induced by light induced by Longjia District in Chengdu increased from 13.5% in 1977 to 68.5% in 1982. Zi Zhong County field insect population density, increased from 6.4% to 75.3%. In the 14,353 victims of field test in Mianyang, 8679 heads of stem borers and 93.01% of stem borer were found. Xinjin, Meishan, Drainage County, Naxi and other places are a similar situation. According to local surveys, in the case of non-control, the second generation of stem borer heart rate is generally about 5%, high up to 20%; second generation can cause white spike, dead bos