Abstract: The occurrence of the key diseases and insect pests in single crop rice system under intensified cultivation has been investigated. Effects of pesticides on non-target diseases and insect pests when the pesticides were used to control targets in rice field was also studied. The results showed that the populations of brown planthopper （Nilaparvata lugens），whitebacked planthopper （Sogatella furcifera），rice leaf folder （Cnaphalocrocis medinalis） and striped stem borer （Chilo suppressalis） under intensified rice cultivation system were increased by 21.7%，27.19%，57.95% and 200.0%，respectively，while the rice sheath blight （Rhizoctonia solani） disease index was increased by 29.10% compared with that under conventional rice cultivation system. Non-target diseases and insect pests were obviously affected by spraying pesticides such as dimehypo，indoxacarb，validamycin，difenoconazole and propiconazole to control striped stem borer，rice leaf folder and rice sheath blight，and the populations of brown planthopper and whitebacked planthopper were all stimulated and proliferated with the increase of 26%-60% than that in conventional rice cultivation system.

Key words: single cropping rice, intensified cultivation, target diseases and pests, occurrence, proliferation