华北棉区玉米田三代棉铃虫种群动态及其对棉田发生为害的作用分析

本文通过玉米田、棉田中对棉铃虫(Heliogyis armigera)种群动态的系统调查和自然种群生命表的分析，明确了玉米田是三代棉钰虫的重要栖境。并且棉铃虫在玉米田的幼期死亡率显著高于棉田。通过棉田三代棉铃虫的影响指数分析，在9个变量中，玉米田与棉田种植面积的比值被确定为主动因素，而棉田二代棉铃虫卵量被确定为关键因素。最后通过当地1973-1991年共19年的资料对上述结果进行了检验，获得了满意的结果。

POPULATION DYNAMICS OF THE THIRD GENERATIONCOTTON BOLLWORMS IN CORN FIELDS OFNORTH CHINA WITH REFERENCE TOITSEFFECT TO COTTON FIELDS

hrough systematical investigation on the population dynamics and analysis ofnatural population life tables of the cotton bollworm Heliothis armigera in both cornand cotton fields in North China, it is concluded that corn fields could serve as themportant habitat of the third generation cotton bollworms and the mortality rate ofimmature cotton bollworms in corn fields exceeded that in cotton fields. Effect indices of the third generation cotton bollworms in cotton fields were manipulated and analyzed. Among the 7 variables the ratio of corn cultivation area to cotton cultivation area was found to be the active factor and the numbers of eggs laid by the second generation in the cotton fields was ascertained as the key factor. These conclu-sions are tested with local data from 1973 to 1991 with satisfactory results.