Artificial rearing of the ladybird Propylea japonica on a diet containing oriental armyworm, Mythimna separata

Three artificial diets were developed and tested for their suitability for immature development and survival of the ladybird Propylea japonica (Thunberg) (Coleoptera: Coccinellidae). The artificial diet based on the oriental armyworm, Mythimna separata (Walker) (Lepidoptera: Noctuidae), resulted in 66.5% survival and was a potential food for mass rearing of P. japonica. The effect of this alternative diet was assessed independently for larval development and adult reproduction by adding various numbers of frozen aphids, and finally an artificial rearing scheme was established that could save about 80% of natural food (aphids). The results showed that the survival rate and fecundity of P. japonica reared on the best artificial diet or aphids alone were similar. A rearing scheme using mainly M. separata‐based artificial diet and a small number of frozen aphids for the mass production of P. japonica became possible. We established an artificial rearing scheme that reduced the required amount of natural food (aphids) to 20% compared to a diet consisting of only aphids. The survival rate and fecundity of Propylea japonica (Coleoptera: Coccinellidae) reared on the best artificial diet or aphids alone were similar. A rearing scheme using mainly artificial diet based on oriental armyworm, Mythimna separata (Lepidoptera: Noctuidae), and a small number of frozen aphids for the mass production of P. japonica is now possible.