University of Florida, IFAS, Gulf Coast Research and Education Center, Wimauma, FL 33598, USA.
Pest Manag Sci. 2010 Feb;66(2):186-95. doi: 10.1002/ps.1853.
Biotype B of the sweetpotato whitefly, Bemisia tabaci (Genn.), is a worldwide pest that has developed resistance to many insecticides, including the neonicotinoid class. Florida field populations were monitored for susceptibility to the neonicotinoids imidacloprid and thiamethoxam using a cut leaf petiole bioassay method.
Average RR(50) values for imidacloprid increased from 3.7 in 2000 to 12.0 in 2003; decreased to 5.0 and 2.5 in 2004 and 2005, respectively; and then increased to 26.3 and 23.9 in 2006 and 2007, respectively. Populations with RR(50) values of about 50 to 60 during generation one reverted to RR(50) values of < or =4 in six generations, when reared without further exposure to imidacloprid. Average RR(50) values for thiamethoxam increased from 2.0 in 2003 to 24.7 in 2006 and decreased to 10.4 in 2007. Populations with RR(50) values of about 22, 32 and 53 during generation one declined to 8, 5 and 6, respectively, after being reared for five generations without exposure to thiamethoxam. The correlation coefficient from the 26 populations that were bioassayed both with imidacloprid and thiamethoxam showed a significant positive correlation (R(2) = 0.58) between these populations.
The high level of RR(50) values to imidacloprid and thiamethoxam suggest an unstable decline in the susceptibility of B. tabaci to imidacloprid and thiamethoxam, with possible cross-resistance or predisposition for dual resistance selection.
甘薯粉虱（Bemisia tabaci）的生物型 B 是一种世界性害虫，它对许多杀虫剂，包括新烟碱类杀虫剂，已经产生了抗性。采用切叶叶柄生物测定法监测佛罗里达州田间种群对新烟碱类杀虫剂吡虫啉和噻虫嗪的敏感性。
吡虫啉的 RR(50)平均值从 2000 年的 3.7 增加到 2003 年的 12.0；分别在 2004 年和 2005 年下降到 5.0 和 2.5；然后在 2006 年和 2007 年分别增加到 26.3 和 23.9。第一代 RR(50)值约为 50-60 的种群在没有进一步接触吡虫啉的情况下，经过六代繁殖后，RR(50)值恢复到 <或=4。噻虫嗪的 RR(50)平均值从 2003 年的 2.0 增加到 2006 年的 24.7，然后在 2007 年下降到 10.4。第一代 RR(50)值约为 22、32 和 53 的种群在没有接触噻虫嗪的情况下，经过五代繁殖后，分别下降到 8、5 和 6。对 26 个用吡虫啉和噻虫嗪进行生物测定的种群进行分析，发现这些种群之间存在显著的正相关（R(2) = 0.58）。
吡虫啉和噻虫嗪的 RR(50)值较高表明，B. tabaci 对吡虫啉和噻虫嗪的敏感性不稳定下降，可能存在交叉抗性或对双重抗性选择的倾向。
