应用赤眼蜂防治玉米螟的放蜂量试验

1987～1988年在辽宁省西丰县、岫岩县等老放蜂区和新民县新放蜂区,进行赤眼蜂防治第一代玉米螟的示范试验。结果证明,由放蜂量1～1.5万头,可以代替过去推广的亩放蜂量2～3万头。用低蜂量示范试验进一步证明,亩放蜂量1万头,在玉米螟中等偏重的发生年份,也能取得比较理想的防治效果,值得推广应用。

FIELD EXPERIMENTS ON THE RELEASING RATE OP TRICHOGRAMMA DENDROLIMI [HYM.:TRICHOGRAMMATIDAE]FOR CONTROLLING ASIAN CORN BORER IN LIAONING

Trichogramma dendrolimi was released at the numbers ranging from 5,000/mu to 30,000/mu (15mu=l ha) in three counties of Jilin in.1987-1988, to assess the optimal releasing rate for controlling the first generation Asian corn borer (ACB), Ostrinia furnacalis. The three releasing sites included two categories: the "Old" sites in Xifeng Co. and Youyan Co. had had previous releases of Trichogramma for many years; and the "New" site in Xinmin Co. had no previous release. The overwintering population level of ACB in the "Old" sites was found to be less than 15 larvae per 100 stocks, while that in the "New" site was 150 larvae per 100 stocks. The results of the two-year experiment in a total area of over 800 ha demonstrated that 10,000-15,000/mu, was the optimal releasing rate, which was recommended to replace the conventional releasing rate of 20,000-30,000/mu. The parasitization rates of ACB eggs were 41.8-84.03% in the "Old" sites, and 66-81.2% in the "New" site.