Abstract: Resistance to three insecticides of the oriental fruit fly,Bactrocera dorsalis(Hendel),adults from Guangdong,Haihan,Fujian,Guangxi Provinces was assayed by vial residue in the laboratory.The results showed that low level of resistance of the fly population from Fujian to abamectin and population from Chenghai and Minnan to trichlorphon were revealed,but other populations tested remained susceptible to trichlorphon,alpha-cypermethrin and abamectin.In 2003 and 2004,the resistance of the fly adults from Gangzhou suburb to five insecticides was monitored by vial residue.It revealed that the resistance were not significantly different except trichlorphon in two years.Effective measures to reduce insecticide resistance selection were needed to sustain the utility of these chemicals in management of the oriental fruit flies in South China.