Optimization of artificial diets for mass rearing of Bactrocera dorsalis, Bactrocera cucurbitae and Bactrocera tau

Key Words：Bactrocera dorsalis, Bactrocera cucurbitae, Bactrocera tau, mass rearing, artificial diet, optimization

Abstract：Artificial diets for adult Bactrocera dorsalis (Hendel) and B. cucurbitae (Coquillett) were evaluated in the laboratory at 25-28℃, 70%-75%RH and a L∶D ratio of 14∶10. A mixture of 1 part sucrose to 2 parts beer yeast by weight was the optimum artificial diet for adults of these two species. The egg quantity per female, egglaying stage and hatching rate were 424.16-445.75 individuals, 30.90-31.87 days and 74.60%-75.40%, respectively. The effects of rearing larvae of B. dorsalis, B. cucurbitae and B. tau (Walker) on 18 different artificial diet formulae were compared. Corn and wheat bran mixtures were found to be better than oatmeal and wheat bran. The optimal formula for an artificial diet for rearing B. dorsalis larvae was 125 g corn, 25 g wheat bran, 25 g sucrose, 25 g beer yeast, 0.9 g methyl p\|hydroxybenzoate, 4 mL 1 mol/L hydrochloric acid, 4 g paper towel and 300 mL tap water. Biological parameters measured in individuals of this species reared on the larval diet were hatching rate of the next generation, pupation rate, emergence rate and average pupa weight. These were 81.17%±0.05%, 96.41%±0.02%, 94.85%±0.01%and 1940±0.08 mg, respectively. By comparison, the optimal artificial diet formula for rearing larvae of B. cucurbitae and B. tau was 100 g corn, 50 g wheat bran, 30 g sucrose, 25 g beer yeast, with the same amounts of the other ingredients as for B. dorsalis larvae. Biological parameters measured in individuals of the two species reared on the larval diet were hatching rate of the next generation, pupation rate, emergence rate and average pupa weight. These were 78.50%±004%and 76.96%±0.12%, 95.73%±0.03%and 94.69%±0.02%, 94.57%±0.02%and 95.82%±0.03%, 18.62±023 mg and 22.83±1.38 mg, respectively. It was found that all three pest species raised on their respective optimal larval artificial diets could be reared successfully for successive generations. The diets are practical for maintaining populations of these three Bactrocera species because they are effective, simple to prepare and the ingredients required are widely available and inexpensive.