Resistance Of Chilo Suppressalis Walker To Triazophos And Its Mechanisms

Rice stem borer, Chilo suppressalis Walker, one of the most important rice pests in China, always damages rice production heavily in the Yangzi River. Since the 90s of last century, it breaks out continuously and become even difficult to be controlled because of its high resistance to different insecticides, which menace the stability of rice production seriously.Triazophos is one of the major pesticides used to control rice stem borer in the field. In order to make good use of this insecticide and practice efficient resistance management, the resistance of the field rice stem borer collected from high resistant area was surveyed. Furthermore, the resistant strain was selected, and the resistance reality heredity(h~2), fitness cost, stability, cross-resistance and resistance mechanism were all tested, and the gene for target enzyme, acetylcholinesterase (AChE) was also cloned for searching its insensitive mutations. The results were summarized as follows:1 Resistance monitoring with field rice stem borerThe rice stem borer collected from Cangnan County, Zhejiang Province was tested for its resistance to some conventional pesticides from 2002 to 2004. The results indicated that in 2002 the field population of rice stem borer had developed resistance to several kinds of pesticides. The resistance ratio for triazophos, fipronil, isocarbophos and methamidophos was 203.3, 18.9, 3.7 and 26.6 fold, respectively. Three years later, its resistance to triazophos and abamectin increased and reached to 2367.3 and 30. But at the same time, its resistance to isocarbophos increased only slightly to 8.4, while to fipronil decreased to 7.4. Further analysis revealed that the resistance of rice stem borer varied with the quantity and the kinds of insecticides used in the field.