亚洲玉米螟对玉米的为害损失估计及经济阈值研究

 1988-1990年在本所农场实验田从不同卵量、不同世代和不同抗性品种三个方面研究了亚洲玉米螟为害与产量损失之间的关系。试验结果表明：玉米螟卵量、蛀孔数及产量之间有显著相关性和回归关系。幼虫为害造成的产量损失在两世代间有显著差异，且与品种抗虫性有关。提出了根据收获前植株上幼虫为害形成的蛀孔数估计产量损失的技术以及根据各代着卵量确定经济阈值的方法。得出防治指标为：中抗品种中原单4号心叶期（一代）和穗期（二代）百株累计卵量分别为20块和12块；感虫品种中单2号心叶期和穗期百株累计卵量均为12块。

YIELD LOSSES AND ECONOMIC THRESHOLD OF ASIAN CORN BORER, OSTRINIA FURNACALIS (GUENEE) ON CORN

Corn yield losses caused by Asian corn borer (ACB), Ostrinia furnacalis (Guenee), at different development stages of corn and injury levels of the insect pest were studied on two single-cross corn hybrids, Zhongyuandan No.4 (leaf-feeding damage rated for 3.5) and Zhongdan No.2 (leaf-feeding damage rated for 7.0) in Beijing from 1988 to 1990. There were significant correlations among the number of egg-masses, holes (ACB stalk damage) and the yield. Significant differences in yield losses were found between the first-generation infested at the whole stage and the second generation infested at the silking stage, and between the two single-crosses as well. It was revealed that the hole number was a more appropriate criterium for evaluating the yield loss than the larva number/plant. According to the experimental data, the economic threshold for the lst and 2nd generations were 20 and 12 egg masses per 100-plant for Zhongyuandan No. 4 and 12 egg masses per 100-plant for Zhongdan No.2 at the whole and the silking stages, respectively.