麦套棉田苗期不施药保护天敌控制害虫的研究

棉蚜是棉田前期的主要害虫,过去一直应用农药防治。1904-1988年,在江苏省射阳县的麦套移栽棉田,进行了6月底前不用农药和施用农药防治棉蚜的对比试验,结果6月底前棉田不用农药防治棉蚜,天敌总数增加47.96％,中、后期害虫减少54.54％,蕾铃期虫害减少58.62％,玉米螟蛀棉茎数明显减少。棉花的生长、产量和品质与施用农药的棉田,差异不显著。作者认为麦套移栽棉田,在雨水调匀,棉株正常生长发育的年份,充分利用棉田天敌的作用,6月底前苗期不施农药防治蚜虫是可行的。

CONSERVATION OF NATURAL ENEMIES IN TRANSPLANTED COTTON FIELDS BY ELIMINATING INSECTICIDE APPLICATIONS IN THE SEEDLING STAGE

In Sheyang County, chemical control has long been the strategy against aphid (Aphis gossypii) infestation of cotton seedlings. In field experiments conducted during 1984-88 in a field where cotton seedlings were transplanted between rows of late season wheat, the overall effect of insecticide treatment vs. no treatment prior to the end of June on pest populations and cotton yields were compared. By the end of June, the total number of various natural enemies increased by 47.9%, mid to late season pests and pests attacking cotton squares decreased by 54.5% and 58.6%, respectively in the no insecticide field. An obvious decrease of cotton stem infestations by ostrinia furnacalis was also observed. No significant difference in the growth, yield and quality of cotton was found between the insecticide treated and no-insecticide fields. It is thus concluded that insecticide applications against the aphid is not necessary and should be eliminated until the end of June.