Tomohisa Fujii1, Sachiyo Sanada-Morimura1, Takaho Oe2, Manami Ide3, Dinh Van Thanh4, Ho Van Chien5, Phan Van Tuong6, Phung Minh Loc6, Le Quoc Cuong5, Ze-Wen Liu7, Zeng-Rong Zhu8, Jian-Hong Li9, Gang Wu10, Shou-Horng Huang11, Gerardo F Estoy12, Shoji Sonoda13, Masaya Matsumura1. 1. Agro-Environment Research Division, Kyushu Okinawa Agricultural Research Center, National Agriculture and Food Research Organization (NARO), Suya Kumamoto, Japan. 2. Department of Crop Protection, Miyagi Prefectural Furukawa Agricultural Experiment Station, Ozaki, Miyagi, Japan. 3. Nagasaki Prefectural Government, Nagasaki, Japan. 4. Plant Protection Research Institute, Ha Noi, Vietnam. 5. Southern Regional Plant Protection Center, Tien Giang, Vietnam. 6. Southern Pesticide Control & Testing Center, Ho Chi Minh City, Vietnam. 7. College of Plant Protection, Nanjing Agricultural University, Nanjing, China. 8. Institute of Insect Sciences, Zhejiang University, Hangzhou, China. 9. College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China. 10. College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China. 11. Department of Plant Protection, Chiayi Agricultural Experiment Station, Taiwan Agricultural Research Institute, Council of Agriculture, Chiayi, Taiwan, China. 12. Agusan Experiment Station, Philippine Rice Research Institute, Basilisa, Philippines. 13. Institute of Plant Science and Resources, Okayama University, Kurashiki, Japan.
Abstract
BACKGROUND: Long-term monitoring data is helpful to understand the fluctuation of susceptibility and pattern of cross resistance in insecticide resistance management. After the occurrence of imidacloprid resistance, the brown planthopper (BPH) has gradually developed resistance to thiamethoxam and clothianidin since 2010, but not to dinotefuran and nitenpyram. Here, we analyzed susceptibilities data of five neonicotinoids during 2005-2017 in East Asia and Vietnam to conduct cross-resistance patterns among neonicotinoids. To determine the factors of development of cross resistance in laboratory bioassays, we used the imidacloprid resistant and control strains that were selected from filed populations in the Philippines and Vietnam. RESULTS: The Linear Mixed Models (LMM) analyses of insecticide susceptibility data showed that the slope values of imidacloprid resistance effects were 0.68 and 1.09 for resistance to thiamethoxam and clothianidin, respectively. Laboratory bioassay results showed that the LD50 values for thiamethoxam and clothianidin in resistant strains (1.4-5.5 μg g-1 ) were 3.2-16.4 times higher than those in the control strains (0.28-1.5 μg g-1 ). However, the increase in the LD50 values for imidacloprid was not related to that for dinotefuran and nitenpyram based on the results of the LMM analysis and laboratory bioassay. CONCLUSION: Our results demonstrate that the development of imidacloprid resistance result in strong-cross resistance to some neonicotinoids, thiamethoxam and clothianidin, but not to others, dinotefuran and nitenpyram. We anticipate that our findings will be a starting point for understanding mechanism of the different trend of cross resistance by analyzing long-term susceptibility data and laboratory bioassays in insect pests.
BACKGROUND: Long-term monitoring data is helpful to understand the fluctuation of susceptibility and pattern of cross resistance in insecticide resistance management. After the occurrence of imidacloprid resistance, the brown planthopper (BPH) has gradually developed resistance to thiamethoxam and clothianidin since 2010, but not to dinotefuran and nitenpyram. Here, we analyzed susceptibilities data of five neonicotinoids during 2005-2017 in East Asia and Vietnam to conduct cross-resistance patterns among neonicotinoids. To determine the factors of development of cross resistance in laboratory bioassays, we used the imidacloprid resistant and control strains that were selected from filed populations in the Philippines and Vietnam. RESULTS: The Linear Mixed Models (LMM) analyses of insecticide susceptibility data showed that the slope values of imidacloprid resistance effects were 0.68 and 1.09 for resistance to thiamethoxam and clothianidin, respectively. Laboratory bioassay results showed that the LD50 values for thiamethoxam and clothianidin in resistant strains (1.4-5.5 μg g-1 ) were 3.2-16.4 times higher than those in the control strains (0.28-1.5 μg g-1 ). However, the increase in the LD50 values for imidacloprid was not related to that for dinotefuran and nitenpyram based on the results of the LMM analysis and laboratory bioassay. CONCLUSION: Our results demonstrate that the development of imidacloprid resistance result in strong-cross resistance to some neonicotinoids, thiamethoxam and clothianidin, but not to others, dinotefuran and nitenpyram. We anticipate that our findings will be a starting point for understanding mechanism of the different trend of cross resistance by analyzing long-term susceptibility data and laboratory bioassays in insect pests.