棉田玉米螟的田间发生为害观察

Observation on the occurrence aud injury of Ostrinia furnacalis(Güenée) in the cotton field

灯下所诱玉米螟Ostriniafurnacalis（Güenée）雌蛾，二、三代分别为76．05％及59．91％，蛾峰后4～5天出现卵峰。主茎叶及棉株下部的卵量随产卵时间的推移，逐渐递减，而趋向棉株上部及外围。二代卵以下部2～3层为多，三代卵以2～4层果枝为多，内围多于外围；93％以上的卵产于绿叶反面；棉田卵寄生的高低与施药有关，且明显低于玉米田；二代5～10层蛀茎占总数的84．44％，三代4～8层蛀铃占59．79％。卵密度不同，蛀铃分布也不同。

this paper reports the location and distribution of the 2nd and 3th generation corn borers eggs on cotton and its harm to the cototn fields. Incubation of eggs, parasitism, nature enemy and transfer harm of larva are also described.