Effects of sequential infestation of the rice leaf folder Cnaphalocrocis medinalis (Guenée) and white-backed planthopper Sogatella furcifera (Horváth) on the physiology and biochemistry of rice plants
Author of the article:JIANG Li-Ben** ZHU Zhan-Fei GE Lin-Quan WU Jin-Cai***
Author's Workplace：School of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China
Key Words：Cnaphalocrocis medinalis, Sogatella furcifera, sequential infestation, sucrose, starch, sucrose synthase, sucrose phosphate synthase
Abstract： [Objectives] To determine the effect of sequential infestation (SI) of the rice leaf folder Cnaphalocrocis medinalis (Guenée) and white-backed planthopper Sogatella furcifera (Horváth) on rice yield loss and on rice plant enzymes. [Methods] The effects of SI and days of infestation (DI) by the rice leaf folder (RLF) and white-backed planthopper (WBPH) on the starch and sucrose content and sucrose synthase (SS) and sucrose phosphate synthase (SPS) activity in the roots, stems and leaves of rice plants were investigated. [Results] Starch and sucrose content, SS and SPS all decreased with increased infestation density. Prior infestation by WBPH had a greater effect on the above biochemical substances than prior infestation by RLF, even with increased DI. For example, the sucrose content and SPS activity in rice leaves subject to prior infestation by RLF significantly increased with increasing of DI so that it was significantly higher after 24 DI than at 6 and 12 DI. In contrast, sucrose content and SPS activity in rice leaves subject to prior infestation by WBPH significantly decreased so that these were significantly lower after 24 DI than at 6 and 12 DI. Similarly, starch content and SS activity in the stems of rice plants subject to prior infestation by RLF increased with increasing DI. In contrast, starch content and SS activity in the stems of rice plants subject to prior infestation by WBPH significantly decreased with increasing DI. Starch content in rice leaves decreased with increasing DI, but SS activity significantly increased in plants subject to prior RLF infestation but decreased in plants subject to prior WBPH infestation. In addition, there was a significant interaction between infestation density and DI.