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根据北京地区春茬西瓜瓜蚜发生规律,按不同益害比释放异色瓢虫,评价其在设施条件下对春茬西瓜瓜蚜的控害能力,并调查最佳益害比条件下天敌和害虫的消长动态。结果表明,在瓜蚜发生初期释放异色瓢虫,益害比1:10的防治效果最佳,可持续控制瓜蚜种群密度,释放7 d防效最高,为85.95%,28 d平均防效仍可达69.12%;在益害比为1∶10时,异色瓢虫与瓜蚜消长规律在一定时间内比较相似,异色瓢虫定殖率在蚜虫暴发期最高,但较瓜蚜滞后5~7 d,最终趋于平衡。
According to the law of occurrence of watermelon aphid in spring in Beijing area, the different color to shade ratio of ladybugs were released to evaluate their control ability against spring watermelon aphid under spring conditions. Growth and decline of pests. The results showed that in the early stage of A. melitensis, the release of Harmonia axyridis was the best, and the ratio of 1:10 was the best. The population density of A. gigas was controlled continuously. Still up to 69.12% .When the ratio of benefit to harm is 1:10, the growth and decline of the ladybird and the ladybird are similar in a certain period of time, and the reproduction rate of the ladybird is the highest in the aphids outbreak, 5 ~ 7 d, finally tends to balance.