Additive insect-resistant effects of transgenic triploid Chinese white poplar against Clostera anachoreta

Two generations of Clostera anachoreta (Fabricius) larvae were fed continuously with leaves of selected clones of transgenic (Bt + API) triploid Chinese white poplar in order to evaluate additive insect-resistant effects of transgenic triploid Chinese white poplar. When the two generations were subcultured with the high and medium level insect-resistant transgenic poplar, the high and medium level insect-resistant transgenic poplar manifested its obvious additive resistance to C. anachoreta (Fabricius), with higher mortality of the second generation C. anachoreta (Fabricius) larvae and longer larvae growth period of the second generation than those of the first generation. Furthermore, the weight of pupa and the fecundity of the second generation were lower than those of the first generation. However, there was no significant difference between both generations when subcultured with low level insect-resistant transgenic poplar. These results implied that the population of C. anachoreta (Fabricius) would decline gradually to under the economic threshold even when planting the medium level insect-resistant transgenic poplars in the environment.