亚洲玉米螟为害棉花及其卵量与为害数量关系的研究

江苏省棉区亚洲玉米螟1年发生3代,各代均可为害棉花。由于耕作制度的不同,各代在棉田内发生为害程度不一。夏玉米—棉花混作区棉田一代发生量大,二、三代很少为害棉花;春玉米—棉花区主要以二、三代为害棉花;邻近玉米区的稻棉区棉田各代均发生为害,发生轻重与距玉米区远近有关,愈近发生愈重。一代幼虫为害棉花形成的被害数与其卵块在棉田内的密度呈线性关系,而二、三代的为害棉花各受害部位数量与卵块密度呈非线性关系。此外,被害量还与卵块在棉田内的分布有关,在一定的面积上,同样的卵块密度分布集中所引起的为害要轻于分布疏的。

THE DAMAGE OF ASIAN CORN BORER TO COTTON AND THE RELATION OF ITS EGG MASS DENSITY TO INJURED ORGAN NUMBER OF COTTON

There are three generations a year of Asian corn borer (ACB) Ostrinia furnacalis (Guenee) in Jiangsu Cotton Area, all of which are capable to damage on cotton. The injured level to cotton varied with different cropping systems, in summer corn-cotton area, high density of first generation and only a few of 2nd and 3rd generations occur in cotton field; while in spring corn-cotton area, the 2nd and 3rd generations are dominant on cotton. In fice-cotton area, the extent of occurrence depends on the distance between cotton field and corn area, the more close distance left, the more heavy damage suffered. The injured organ number of cotton was lineally related to the egg mass density of first generation but non-lineally to that of 2nd and 3rd generations. Besides, the injured organ number of cotton was also related to the spatial distribution of egg mass of ACB in cotton field, under the same egg mass density, the sparse distribution of egg mass caused heavier damage than the aggregate one.