Artificial diet for mass-rearing of melon borer, Diaphania indica (Saunders) (Lepidoptera: Pyralidae)

Abstract

The melon borer, Diaphania indica (Saunders) (Lepidoptera: Pyralidae), is a serious pest of tropical and subtropical cucurbitaceous vegetables. A suitable artificial diet is desirable for producing uniform insects for commercial purposes or research. Four new artificial diets (D-1, D-2, D-3 and D-4) and bitter gourd, the natural host plant of D. indica, were used for rearing D. indica, and the life parameters were compared. The results indicated that insects could complete a full life cycle after 3 generations, only when the larvae were fed bitter gourd or the diet D-1.The new artificial diet, D-1 was formulated based on bitter gourd leaves, Momordica charantia (L.) and chick pea, Cicer arietinum L. Developmental parameters like egg hatching, larval duration and longevity of the adult reared on the D-1 artificial diet were found to be significantly improved relative to the other three diets (D-2, D-3 and D-4), but were not significantly better than those reared on the host-plant bitter gourd. However, the rearing efficiency (i.e., larval - pupal survival, developmental duration of pupa and fecundity of adults,) on the D-1 diet was on par with the rearing efficiency on bitter gourd. There were no significant changes in reproductive potential after five successive generations of rearing on the new diet. These results indicated that the newly developed diet could serve as a viable alternative to bitter gourd plant for continuous rearing of D. indica.