新疆南部高密度棉田二代棉铃虫种群自然消亡因子及其危害损失分析

新疆南部主要棉区高密度棉田二代棉铃虫消亡因子主要可以归纳为天敌捕食、寄生、生理死亡、自然损失及人为活动等5个因子.1龄、5～6龄幼虫以及卵是新疆南部主要棉区二代棉铃虫田间自然消亡的主要阶段.各龄期幼虫田间自然存活率分别为53.3;、14.93;、10.60;、8.16;、6.69;、4.62;和2.58;.新疆南部棉产区二代棉铃虫总消亡率为97.95;,种群趋势指数(Ι)为8.877 8.单头二代棉铃虫幼虫蛀食蕾数为0.921～14.35,平均4.92个,其数量与棉花蕾、花、铃数量减少率和产量损失呈正相关,综合棉铃虫危害和当前高密度棉花种植的生产成本,其防治指标为102粒卵/百株.

Natural Dying out Factors of Population Dynamic of Second Generation Bollworm and Analyse of Its Damage in High Density Cotton Field of the Southern of Xinjiang

The main dying out factors of the second generation bollworm in south high density cotton field are:being caught and fed by natural enemy,paratism,physiological dying natural loss and artificial action etc.The main period of natural dying out of the second bollworm in south main cotton area are:1st,5～6th aged larva and eggs period.Thelivingrateofeachinsectagelarvainfieldare:53.3%,14.93%,10.6%,8.16%,6.69%,4.62%,2.58% respectively.The total dying out rate of the second generation bollworm acount for 97.95% the popwatiom tending index(I) is 8.877 8.The eating bud rate of each second generation bollworm larva is 0.912～14.35,the average is 4.92 ,this amount is interrelated with the decrease rate of cotton bud,flower and boll and the decrease production of cotton positively,synthesize the damage of bollworm and the production cost of high density cotton cultivation now,the index of prevention and cure is 102 eggs/100 cottons.