Mass rearing of the rice leaffolder, Cnaphalocrosis medinalis (Guenee) (Lepidoptera: Pyralidae), on an artificial diet.

To develop a mass rearing method for the rice leaffolder, the influences of adult density on oviposition by females, the optimum rearing density of larvae, and the method of collecting pupae were investigated. Although the adult density did not affect the total number of eggs laid by a female, the pattern of egg laying was more concentrated to early adult life at high densities, and thus more eggs were obtained in a day. When 10 pairs of adults were released in a polyethylene bag, more than 200 eggs were collected daily for 4 d after the first oviposition. For rearing larvae, a density of 100 larvae in a rearing container (15X20X5 cm) seemed appropriate for mass rearing. Pleats of paraffin sheets corrugated at 5-mm intervals placed on the food were shown to be suitable as pupation substrates. The pupae could be collected easily by simply spreading the sheet.