Resistance Selection of Myzus persicae to Imidacloprid and Its Cross-resistance to Other Insecticides

The resistant strain of peach-potato aphid, Myzus persicae (Sulzer) to imidacloprid was continuously selected by leaf-dip bioassay in the laboratory. The imidacloprid-resistant strain with 14.34-fold resistance was developed after 15-generation selection. The cross-resistances of the imidacloprid-resistant strain to nine insecticides commonly used in the tobacco field were also measured. It appeared to have positive cross-resistance to pyrethroids including lambda-cyhalothrin (resistance index was 12.76-fold) and deltamethrin (10.24-fold). It also had cross-resistance to organophosphates such as omethoate (7.95-fold), phoxim (5.44-fold), methamidophos (5.32-fold) and the mixture of imidacloprid and beta-cypermethrin (8.90-fold). However, it had no cross-resistance to carbamate (methomyl), organochlorine (endosulfan) and the mixture of abamectin and phoxim.