Induced resistance to rice blast disease in rice plants infested with the white-backed planthopper, Sogatella furcifera, in a paddy field

The incidence of rice blast disease caused by Magnaporthe grisea in rice plants infested with the white-backed planthopper, Sogatella furcifera, was studied under field conditions. Pesticides, fipronil or imidacloprid were used to control the occurrence of S. furcifera in paddy fields. A comparison was made for the incidence of rice blast in paddy fields treated and not treated with pesticides. The results showed that the development of blast lesions was higher on rice plants in paddy fields where fipronil or imidacloprid was applied as compared to those plants in paddy fields where the pesticides were not applied. Moreover, the number of blast lesions was significantly smaller on rice plants that had previously been exposed to infestation with S. furcifera as compared to plants that had not been infested. These results show that infestation with S. furcifera induced disease resistance in the rice plants, thereby reducing their susceptibility to M. grisea.