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1979—1983年作者探讨了稻纵卷叶螟Cna[halocrosis medinalis为害的产量损失和防治指标,通过大田调查,控虫观察与模拟试验后,肯定剑叶被害后减产9.3—20.3％(秈稻)和10.7—15.6％(杂交稻);全部叶片被害后减产26.5—36.7％(秈稻)和30.2—44.3％(杂交稻)。其减产程度是抽穗期>分蘖期>乳熟期。而防治指标因稻生育期不同:分蘖期为丛平均有三龄幼虫0.75—1.4条;抽穗期为平均0.5—0.7条。在天敌少时采用指标的上限,反之,使用下限。抽穗期是防治关键。生长嫩绿的稻田是防治的重点对象。这些指标曾在五万余亩稻田示范后,功效十分显著。
From 1979 to 1983, the authors investigated the yield loss and control index of Cna [2]. After field investigation, pest control observation and simulation test, the authors affirmed that yield reduction of 9.3-20.3% (indica) 10.7-15.6% (hybrid rice); 26.5-36.7% (indica rice) and 30.2-44.3% (hybrid rice) were cut after all the leaves were killed. The yield reduction is heading stage> tillering stage> milky stage. The control index due to different rice growth period: the tillering average of the third instar larva 0.75-1.4; heading for an average of 0.5-0.7. In natural enemies less indicators of the upper limit, on the contrary, the lower limit. Heading is the key to prevention and treatment. Growing green rice is the focus of prevention and control. After these indicators have been demonstrated in more than 50,000 acres of paddy fields, their effectiveness is very significant.