[Population dynamics of pests and their enemies in different cultivated rice fields]

Through a whole year field investigation, this paper analyzed the population dynamics of pests and their enemies in organic and normally cultivated rice fields. The results indicated that the population of main pests varied more lightly in organic than in normally cultivated rice field, while subordinated pest species had little difference between these two fields. The individuals of enemies were more in organic than in normally cultivated rice field. It is suggested that the pest-control effect of enemies could be restored and became stronger when no chemical pesticides were applied.