棉区夏玉米田害虫及天敌群落结构

1997年7月8日至8月29日系统调查了夏玉米田主要害虫及天敌的种群数量动态，并利用相对多度、丰富度、优势度、生态优势度、多样性指数和均匀度分析了其群落结构和动态。结果表明：（1）在棉区夏玉米田共有害虫和天敌59种，其中害虫24种，天敌35种。（2）截形叶螨为优势种，其优势度指数为0.6459-0.9924。（3）8月中旬以后群落多样性指数（H′）和均匀度（J）较大，分别为0.7327-0.9378和0.5242-0.6986；但此期以前，H′与J均较小，应注意防治。（4）害虫及天敌在时间上的同步性和在空间上的同域性均强，为保护利用自然天敌控害提供了依据。最后分析提出了以保护利用天敌为主的综合防治策略和措施。

ON THE COMMUNITY STRUCTURE OF MAJOR INSECT PESTS AND NATURAL ENEMIES IN SIMMER CORN FIELD INLAID IN COTTON AREA

The population dynamics of major insect pests and natural enemies in summer corn field inlaid in cotton area were investigated in July 8 - August 29 in Chengwu County, Heze Prefecture, Shandong Province. Based on the data of relative richness, abundance, dominance, ecological dominance , diversity index and evenness, the dynamics of community structure were analysed. The results showed that: (1) There were 59 species of insect pests (24 species) and natural enemies (35 species) in this corn field. (2) Tetranychus truncatus Ehara was the dominant species, its dominant indices ranged from 0.6459 - 0.9924. (3) Since late August, the indices of diversity (H' 0.7327 - 0.9378) and evenness (J 0.5242 - 0.6986) were rather high, while before this period, owing to the too low H' and J values, certain other control actions should be taken. (4) Both the time synchronism and space sympatry between major insect pests and their natural enemies in this period were desirable, indicated that it was suitable time to give play to the control effect of natural enemies on insect pests. Finally, a series of IPM measures, with stress on the preserve and use of natural enemies, were proposed.