Development and reproduction of Grapholita molesta (Lepidoptera: Tortricidae) on the 3 artificial diets in the laboratory

Grapholita molesta (Busck) (Lepidoptera: Tortricidae) is a major pest of many fruit trees. The large-scale artificial propagation technology of the insect is the basis for the field application of the sterile insect technique and biological control products based on host mass reproduction. However, a low-cost diet with easily accessible materials remains lacking. In this study, we assessed the insect rearing performance feeding on 3 artificial diets: D1: an artificial diet based on wheat bran and soybean powders; D2: an artificial diet based on soybean powder, maize powders, and tomato sauce; and D3: an artificial diet based on soybean powder, maize powder, tomato sauce, and wheat bran, with apples as a control, using 2-sex life table. At 26 ± 1 °C, 70 ± 5% humidity, and 16:8 h L:D photoperiod, the biological indicators of G. molesta fed D1 were consistent with those fed apples, with a larval stage of 14.88 d, a pupal stage of 7.57 d, adult longevity of 22.69 d, egg deposition count of 223.22, intrinsic rate of increase (r) of 0.1359, finite rate of increase (λ) of 1.1456, and net reproductive rate (R0) of 94.50. D1 was used to continuously rear G. molesta population for 5 generations, all life parameters remained normal. These results indicated that the artificial diet based on wheat bran and soybean powder could be used for rearing of the insect. This study proposes an available and cost-effective artificial diet for G. molesta, facilitating the application of green prevention and control technology.