Rearing pieris brassicae (L.) on semi-synthetic diets with and without cabbage

Abstract

Larvae of Pieris brassicae (L.) were reared very successfully on a semi-synthetic diet containing a small amount (1·4% by wt.) of dried powdered green Brassica leaves. At 20°C., development of newly hatched larvae to the time when 50 per cent, had pupated took an average of 23 days, as compared with 21 days for larvae fed on fresh cabbage leaves. Pupal weights and emergence of adults were normal. The cabbage-leaf powder could be omitted if it was replaced by sinigrin and linseed oil, but on this diet development was prolonged by a further one or two days and the average pupal weights were lower. It seems likely that the stocks could be maintained indefinitely on either of these diets. The larvae made satisfactory growth on standard diet which had been stored at – 20°C. for two months.