Impact of Day Intervals on Sequential Infestations of the Rice Leaffolder Cnaphalocrocis medinalis (Guenée) (Lepidoptera: Pyralidae) and the White-Backed Rice Planthopper Sogatella furcifera (Horváth) on Rice Grain Damage

The present study illustrates that different day intervals (DIs) between the sequential infestations of two pest species, the rice leaffolder (RLF) Cnaphalocrocis medinalis Guenée (Lepidoptera: Pyralidae) and the white-backed rice planthopper (WBPH) Sogatella furcifera Horváth (Hemiptera: Delphacidae), have a significant impact on the rice yield loss rate (YLR) and on the carbohydrate contents of rice plants. For WBPH release after RLF release (WRARR), the YLR decreased with the increasing DIs, and the YLR at the 24 DI was significantly lower compared to that at the 6 and 12 DIs and had a minimum value for a simultaneous infestation of the two pest species (SITS). In contrast, for RLF release after WBPH release (RRAWR), the YLR at the 24 DI had a maximum value and was significantly higher compared to that at the 6 and 12 DIs and the SITS. These findings indicate that damaged rice plants gradually recover, with an increase in the DI for WRARR. The above results were demonstrated by biochemical tests. Therefore, the sequential infestation of the two pest species and their DIs should be considered for integrated pest management (IPM) and control strategies for rice pests.