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1960—61连续二年在河北衡水施用颗粒剂防治玉米螟:春、夏玉米心叶末期用5% DDT 颗粒剂,不仅前期的螟虫减少了80—90%左右,穗期的螟害也适当地被控制。1次施药能减少整个春玉米生育期的虫数65—77.4%,夏玉米60—71.9%。防治效果似与玉米后期虫口密度有关。心叶期防治以在心叶末期为最理想,提早施药不能获得最高效果。心叶期防治2次与防治1次的效果没有差异。心叶末期与穗期各防治1次,收获时检查,防治效果春玉米上可达85.8—88.6%,夏玉米90.6—91%。因此,在螟害较轻的年分,防治1次即能解决大部分的螟害问题,大发生年分,可以在穗期再防治1次。试验证明不同载体、不同加工方法配制的颗粒剂、不同用量和不同施用方法的防治效果差异都不显著。虽然含5% DDT 或0.5—1%666的颗粒剂的残效能维持1个月以上,但由于田间植株上残存的颗粒剂损失很快,1个月后的残存量仅为12—15%,因此1次防治的效果受到限制。由于防治效果与施药时螟卵发生的情况关系不大,而心叶未期是防治最适时期,因此作者建议可以玉米生育阶段作为施药时期的标准。
1960-61 Two years in a row in Hebei Hengshui Granules control corn borer: spring, summer corn heart late 5% DDT granules, not only the early stem borers reduced by about 80-90%, the stem borer is also appropriate controlled. One application can reduce the entire spring corn growth period of 65-77.4% of the number of insects, summer corn 60-71.9%. The control effect seems to be related to the density of insect population at the late stage of corn. Prevention and treatment of heart and leaf at the end of the heart for the best, early application can not get the highest results. There are no differences in the effect of prevention and treatment of heart 2 times and prevention and cure 1 times. Leaf end of the control and the end of a panicle 1, check the harvest, the control effect of up to 85.8-88.6% on spring corn, summer corn 90.6-91%. Therefore, in the light year of stem borer, control 1 times that can solve most of the pest damage problem, the occurrence of major points, you can control again in the spike. Experiments show that different carriers, different processing methods of the preparation of granules, different dosage and different methods of application of the control effect is not significant difference. Although the residual efficiency of granules containing 5% DDT or 0.5-1% 666 was maintained for more than 1 month, the residual amount of residual granules in field plants was very fast and the residual amount after 1 month was only 12-15% Therefore, the effect of a control is limited. As the control effect is not related to the occurrence of rice borer eggs when spraying, but the dead leaves are the most suitable period for prevention and treatment, the author suggests that the corn growth stage can be used as the standard for the application period.