一、发生特点1.发生时间早。1992年二代棉铃虫6月7日见卵,6月12日就达初盛期,卵始期、盛期均为历史最早年份。发生期比常年早5～7天。2.持续时间长。1992年卵期自6月7日至7月4日,长达28天,比常年长8天左右; First, the occurrence of characteristics 1. Occurs early. 1992 second-generation cotton bollworm saw eggs on June 7, June 12 up to the initial stage of the beginning of the egg, peak are the earliest years of history. Occurrence earlier than usual 5 to 7 days. Long duration 1992 egg period from June 7 to July 4, up to 28 days, about 8 days older than usual;