Interfering the mating of Chilo suppressalis (Walker): A new role of sex pheromones ((Z)-11-Octadecen-1-ol and (Z)-13 Octadecen-1-ol) from Cnaphalocrocis medinalis Guenee

The rice stem borer, Chilo suppressalis (Walker), and the rice leaf folder, Cnaphalocrocis medinalis Guenee are two of the most destructive lepidopteran pests in rice. Since these two lepidopteran insects show occurrence laps in rice paddy fields, farmers prefer to set the pheromone-baited traps of C. suppressalis accompany with the pheromone traps of C. medinalis in the rice fields for convenient observation. However, our field observation demonstrated that no male of the rice stem borer was captured in the traps baited with commercial C. suppressalis sex pheromone (CCS) combined with commercial C. medinalis sex pheromone (CCM). To confirm the C. medinalis sex pheromone component(s) to interfere with the attraction of males of the rice stem borers to their conspecific female moths, the single component of C. medinalis sex pheromone combined with CCS in traps were tested in the laboratory and in the rice paddy field. The results revealed the two alcohol components in CM, i.e., (Z)-11-octadecen-1-ol (Z11-18:OH) and (Z)-13-octadecen-1-ol (Z13-18:OH) may cause a significant reduction in the captures by CCS to C. suppressalis males. We recommend against using these sex pheromones together in the field and suggested that Z11-18:OH and Z13-18:OH could be potential inhibitors or antagonists of C. suppressalis sex pheromone to control the rice stem borer in practice.