Optimization the dietary nutrient composition for mass-rearing of Cydia pomonella (Lepidoptera: Tortricidae)

The codling moth, Cydia pomonella (Linnaeus) (Lepidoptera: Tortricidae), is a notorious invasive pest that poses global pome fruit and walnut production. Long-term chemical insecticide use has led to resistance and residue problems, highlighting the need for sustainable alternatives. The Sterile Insect Technique (SIT) offers an eco-friendly, species-specific pest control strategy but relies on large-scale mass rearing with optimized artificial diets. In this study, we assessed the impact of dietary nutrients in artificial diet on C. pomonella development and fecundity. Results demonstrated that sucrose, yeast powder, choline chloride, and mineral salt mixture supplement did not significantly influence larval and pupal survival. While sucrose minimally affected pupal weight and choline chloride slightly influenced development and longevity, other nutrients had variable effects on C. pomonella growth. Furthermore, the supplement of sucrose, choline chloride, and mineral salt mixture at concentrations of 17.65 or 35.30 g/kg, 1.76 or 3.53 g/kg, and 2.65 or 5.30 g/kg, respectively, resulted in a notable enhancement of female fecundity. Compared to the original diet, the optimized diet (containing sucrose 17.65 g/kg, yeast powder 13.24 g/kg, choline chloride 1.76 g/kg, mineral salt mixture 2.65 g/kg) resulted in a reduction of pupal duration and significant enhancements in the Intrinsic rate of natural increase (r), finite rate of increase (λ), and net reproductive rate (R0) of the populations. Furthermore, adult dietary supplementation with 20% sucrose significantly enhances fecundity. Dietary optimizations for larval and adult stages markedly improve the reproductive performance and mass-rearing efficiency of C. pomonella, facilitating future SIT applications for pest control.