Abstract: Systematic investigation and analysis of insect communities in wheat fields was carried out from April to July,2003.The results indicated that there were 11 orders,23 families,36 species of insects including 4 orders,5 families,12 species of predators; 2 orders,3 families,4 species of parasitoids; 5 orders,12 families,15 species of phytophagous insects ,and 1 order,3 families,5 species of others.Ladybird beetles were the most abundant in species and quantity among the predators,and green lacewings and syrphid flies were secondly.Among the parasitoids,the aphid parasitoid was the most dominant and then the larvaevorids.The English grain aphid Macrosiphum avenae was the most dominant,and the rice leaf bud Trigonotylus ruficornis,the small brown planthopper Laodelphax striatellus and the rice phloeothrips Haplothrips aculeatus were the next.Natural enemies occurred after pest insects and could not control the English wheat aphid efficiently.Based on the component structure of insect communities and wheat developmental period,the seasonal dynamics of insect communities in the wheat fields was divided into five periods using the best division method of sequent samples,and the community characteristics and control strategies in different periods were given.

Key words: Municipal sludge, Chemical fertilizers, Ipomoea aquatica, Paddy soil, Phthalic acid esters (PAEs)