Avermectin is a hexadecyl macrolide compound with insecticidal, acaricidal and nematicidal activities, which was first developed by Tomo Omura et al., Kitasichi University, Japan and Merck Company, USA. It is produced by Streptomycesavermitilis. Naturally occurring avermectin contained eight components, four of which were A1a, A2a, B1a and B2a, and the total content was more than 80%. The corresponding four homologues with smaller proportions were A1bChemicalbook, A2b, B1b, and B2b, whose total content was â?¤20%. At present, the commercial avermectin pesticide is based on abamectin as the main insecticidal ingredient (avermectin B1a+B1b, in which B1a is not less than 90% and B1b is not more than 5%), and it is calibrated by the content of B1a. Since abamectin entered the pesticide market in 1991, avermectin pesticide has played an important role in the pest control system in China.
