Author
WANG, YAN HUA - Nanjing Agricultural University | |
GAO, CONG FEN - Nanjing Agricultural University | |
Zhu, Yu Cheng | |
CHEN, JIN - Nanjing Agricultural University | |
LI, WEN HONG - Nanjing Agricultural University | |
ZHAUANG, YONG LIN - Nanjing Agricultural University | |
DAI, DE JIANG - Nanjing Agricultural University | |
ZHOU, WEI JUN - Nanjing Agricultural University | |
MA, CHONG YONG - Nanjing Agricultural University | |
SHEN, JIN LIANG - Nanjing Agricultural University |
Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 1/7/2008 Publication Date: 4/15/2008 Citation: Wang, Y., Gao, C., Zhu, Y., Chen, J., Li, W., Zhauang, Y., Dai, D., Zhou, W., Ma, C., Shen, J. 2008. Imidacloprid susecptibility survey and selection risk assessment in field populations of Nilaparvata lugens(Stal)(Homoptera: Delphacidae). Journal of Economic Entomology. 101(2):515-522. Interpretive Summary: The brown planthopper is an important rice pest. Control of the insect relies mainly on chemical insecticides, especially the imidacloprid. Since the first introduction in the early 1990s, imidacloprid has maintained high efficacy and long residual effect against the pest. To monitor susceptibility levels to the insecticide, comprehensive surveys were conducted from 1993 to 2006 at 27 locations in eight provinces. Results showed that the brown planthopper maintained susceptibility to imidacloprid before 2003. Surveys conducted in 2005 and 2006 demonstrated that the insect quickly developed up to 811-fold resistance to imidacloprid. Heavy selection pressure due to extensive and intensive use of the insecticide might be the driving force for the resistance development. Laboratory selection analysis provided evidence that the insects receiving more frequent treatment of imidacloprid evolved resistance faster than the insects receiving less frequent treatment of the chemical. Resistance management strategies were also discussed for delaying and slowing down resistance development Technical Abstract: Imidacloprid has been used for many years to control the brown planthopper, Nilaparvata lugens (Stål) in China. To provide resistance assessment for the national insecticide resistance management program, we collected a total of 42 samples of the planthoppers from 27 locations covering 8 provinces to monitor their dose responses and susceptibility changes to imidacloprid over an eleven-year period (1996-2006). Results showed that most field populations maintained susceptibility from 1996 to 2003 except for a population from Guilin, Guangxi in 1997 which showed a low level of resistance to the chemical. However, surveys conducted in 2005 indicated that 16 populations from 6 provinces quickly developed resistance to the chemical with resistance ratios ranging from 79 to 811. The data collected in 2006 revealed that the resistance levels in 12 populations collected from 7 different provinces decreased slightly (RR=107-316), except the Tongzhou population (Jiangsu province) which developed 625-fold resistance to the chemical. Dominant and intensive use of imidacloprid in a wide range of rice growing areas might be a driving force for the resistance development. Migration of the insect also significantly boosted the resistance levels due to extensive and intensive use of imidacloprid in emigrating areas and continuous post-migration sprays of the chemical. In addition, laboratory risk assessment of resistance to imidacloprid showed that N. lugens evolved resistance at a much faster pace under a continuous selection scheme than under non-continuous selection scheme, suggesting that quick resistance development might be associated with more frequent applications of the insecticide in recent years. |