Three consecutive generations of Hypsipyla robusta Moore (Lepidoptera: Pyralidae) were reared on the McMorran–Grisdale Diet (MGD) medium. Mortality rates among the older larvae were consistently low (less than 1.0%) but high (up to 50%) in the first instar stage which was due primarily to escapism and non-feeding. Developmental period from egg to adult was not adversely affected by the artificial diet and ranged between 29 and 41 days. However, a comparison of numbers of larval instars and pupal sizes indicated that the nutritional quality of the MGD and natural food sources differed appreciably. A longterm study to evaluate the usefulness of the MGD for planned mass rearing programmes of H. robusta is recommended.
