杀虫剂对烟地节肢动物群落的影响

研究了烟地条件下施用劲丹、乐果对烟地节肢动物群落的影响，施药后害虫和天敌的种群消长动态，并以多样性、相似性指数等生态学参数来衡量2种杀虫荆产生的生态效应及对烟地节肢动物群落在空间的分布影响。结果表明，施用乐果地块的节肢动物各类群数量明显下降，天敌恢复缓慢，而害虫恢复较快。群体数量的急剧变化使得群落稳定性降低；花用劲丹的地块，烟青虫、蚜虫、蝽类等害虫数量明显下降，且不易恢复，对天敌影响不大。初步认为，使用劲丹杀虫剂对烟地生物群落物种数量的恢复与保持群落的自我调节能力与自然控制力有重要作用。

EFFECTS OF INSECTICIDES ON ARTHROPOD COMMUNITY IN TOBACCO FIELDS

In a field experiment the pesticides Jin Dan and dimethoate were sprayed to tobacco plants and their effects on arthropod community were investigated. The dynamic fluctuation of the insect pests and their natural enemies were monitored after pesticide spray and the ecological parameters "diversity index" and "similarity index" were used to evaluate the ecological effects of the pesticides and their influence on the spatial distribution of the arthropod community in the tobacco fields. The results showed that dimethoate spray markedly decreased the number of various arthropods in the fields and that the pests recovered quickly while their natural enemies recovered comparatively slowly. The abrupt fluctuation of the population number disturbed the stability of the community. In contrast, in the plots sprayed with Jing Dan the number of tobacco pests dropped sharply while the number of their natural enemies was little influenced. Such results suggest that the use of Jing Dan is beneficial to the recovery of the number of species of the biological community in the tobacco fields and to the maintenance of its self-adjustment ability.