Effect of nitrogen fertilizer on the development and fecundity ofSchizaphis graminum (Rondani)
Author of the article:LI Zhi** LIU Xiao-Xia ZHANG Qing-Wen***
Author's Workplace：College of Agriculture and Biotechnology, China Agricultural University, Beijing 100193, China
Key Words：nitrogen fertilizer, Schizaphis graminum, intrinsic rate of increase, soluble sugar, soluble protein
Abstract： [Objectives] To explore the relationships between nitrogen fertilizer application and wheat aphid developmental duration and fecundity. [Methods] The developmental duration and fecundity of the aphid Schizaphis graminum (Rondani) and the amount of foliar soluble protein and soluble sugar in wheat were measured on wheat plants treated with different amounts of nitrogen fertilizer. [Results] The developmental duration of aphids decreased with increasing nitrogen levels and fecundity was significantly higher at 600 mg/L nitrogen than at 60 mg/L, 150 mg/L and 300 mg/L nitrogen. The intrinsic rate of increase, net value-added rate, finite rate of increase and the amount of population increase were lowest at 150 mg/L nitrogen. Foliar soluble sugar increased, and foliar soluble protein decreased, with increasing of nitrogen. Wheat aphids’ intrinsic rate of population increase was significantly, negatively correlated with the amount of foliar soluble sugar but significantly, positively correlated with the amount of foliar soluble protein. [Conclusion] Different nitrogen levels affected wheat aphids’ fecundity and population growth by changing the amount of foliar soluble sugar and soluble protein in wheat plants.