Resistance Monitoring Of Conventional Insecicides In Brown Planthopper, Nilaparvata Lugens (Homoptera:Delphacidae)

The brown planthopper (BPH) Nilaparvata Lugens (Stal)> one of the major migratory insects on rice in Asia for a long time. So far, chemical control is still a major method for suppressing N. lugens. However, there is a rapid increase in resistance of N. Lugens to the maior insecticides such as buprofezin, thiamethoxam, pymetrezine. Therefore, it is important to study the susceptibility or resistance to conventional insecticides On the basis of the resistance monitoring, we amalyzed the temporal variation of the brown planthopper to common insecticides, in order to know the variation of the resistance about BPH in year-over-year and in the different areas. The results could provide basis for insecticide resistance management of the brown planthopper, N. Lugens.1Insecticide resistance monitoring in N. LugensIn order to design the scientific management strategies, it is necessary to know the current situation of resistance to conventional insecticides in N. lugens. The resistance to7insecticides of field populations of N. Lugens from different localities was determined by rice dipping methods in2011and2012. The results showed that substantial variations of the resistance level to different insecticides existed in N. lugens. Field populations developed low to extremely high level (RR=6.9-183.8fold) resistane to buprofezin in2011and2012, respectively. High or extremely high resistance level still kept to imidacloprid (RR=82.3-1935.8fold). Field populations developed moderate to high level (RR=10.6-84.5fold) to thiamethoxam in2011and2012except Guilin Guangxi (2011). For insecticides such as chlorpyrifos, butene-fipronil and nitenpyram, the resistance ratios were in the range of1.4-6.4fold,1.0-7.3fold and1.5-6.4fold respectively. Field populations were medium resistance level to pymetrozine (RR=15.7-25.4fold) in2011, but in2012, the field populations have developed low to extremely high resistance level to this insecticide (RR=4.0-1168.6fold).2Insecticide resistance detecting and monitoring to the source areas of N. lugens in chinaIn order to know the resistance to the source areas of BPH in china, we tested the resistance to six insecticides for N. lugens which collected from Vietnan, Myanmar and Thailand in2011and2012. The results showed that there were different level resistances to buprofezin (RR=7.0,24.9and79.6fold). High or extremely high resistance level still kept to imidacloprid (RR=232.4-553.3fold). To thiamethoxam, the resisitance level were from moderate to high level (RR=20.9-42.7fold), the field populations showed susceptible to chlorpyrifos, butene-fipronil and nitenpyram and susceptible to low resistance level to pymetrozine (RR=3.7-7.2fold).