棉红铃虫田间种群消长及杀虫剂对其影响的初步研究

本文是报道1977～1980年棉花红铃虫Pectinophora gossypiella(Saun-ders)田间种群消长及杀虫剂对其影响。研究结果表明红铃虫成虫数及卵量在上海郊区除1977年外,基本表现为逐代递增的第三代多发型;1977～1980年蛾量与卵量发生不一致,这与成虫产卵期的气侯因子有关。红铃虫第二、三两代的卵量和棉铃被害关系密切。第二、三两代产卵盛期这一批的卵孵化后为害棉铃的程度,在8月上中旬和10月中旬前后吐絮花中的单铃幼虫数中得到反映。由于每年红铃虫发生量不同,杀虫剂对其影响也有差异。在发生轻的年份7～9月用药2～4次其单铃幼虫数与对照比较,其差异不显著。但中等发生年与大发生年,在第二代、第三代成虫产卵高峰前各用药一次可以减少虫50％以上。这表明可以减少田间用药次数。作者另对红铃虫第一代是否要进行防治,第二、三代的防治指标以及早期用药对棉田天敌影响等问题进行了讨论。

PRELIMINARY STUDY ON FIELD POPULATION OF PINK BOLL WORM AND THE EFFECT OF INSECTICIDES

The article deals with the study on field population dynamics of Pectinophora gossypiella (Saunders) and the effect of application of insecticides on them during the period of 1977-1980. The number of adults of the pink bollworm increased gradually from 1st to 3rd generation in Shanghai Suburbs,except the year of 1977,forming the 3rd generation thriving patterns.The fluctution of population of the adults and eggs in 1977 and 1980 was due to weather during the ovipositing period The peak period of oviposition of the 2nd and 3rd generation occuredon Aug.5-10 and Sept.5-10 respectively.The degree of damage caused by the 2nd and 3rd generation larvae could be seen from the number of mature larvae per boll. The effect of insecticides applied on the pink bollworm were different owing to different population densities.In years of light infestation,suchas 1977,the number of larvae per boll was not significant between thetreated and check plots or between the plots with one or 4 applicationsof insecticides.Whilen years of medium or serious infestation.the density of larvae could be reduced more than 50% when the 2nd and 3rd generations were given one application each before the peak of oviposition. Thus,the present study shows the possibility to reducing insecticide application in certain years.