Abstract:In order to establish fast and efficient bio-control effect evaluation technique of ragweed, Ambrosia artemisiifolia, the canopy imaging spectrometer technique was used to detect the canopy spectrum reflectance of ragweed and to evaluate the control efficiency of flea beetle, Ophraella communa, on ragweed. The results showed that the damage of O.communa could cause the canopy spectrum reflectance changes of ragweed. The canopy reflectance of ragweed decreased with the increasing damage level of O.communa at 560 nm within the green light region and 710 to 810 nm within the near-infrared light region, whereas that at 660 nm within the red light region increased with the increasing damage level of O.communa. And the normalized difference vegetation index (NDVI), ratio of vegetation index (RVI), difference vegetation index (DVI) and renomalized difference vegetation index (RDVI) of ragweed fed by flea beetles were all less than that of CK. The canopy spectrum reflectance at the green light region of 560 nm and the near-infrared light region of 710 nm and 760 nm was significantly negatively correlated with the damage level of O.communa. The results indicated that the wavelengths of 560 nm, 710 nm and 760 nm can be used to evaluate the control efficiency of O.communa on A.artemisiifolia when using a multispectral radiometer.