Mass Rearing of Spodoptera litura using a Semi-Synthetic Diet Based on Wheat Germ and Tomato Paste

Spodoptera litura (Hubner) (Lepidoptera: Noctuidae), is the threatening pests of many plants including tomatoes. In vitro, mass-rearing of S. litura is essential to attain a large number of insects with good quality for bio-ecological studies and biological control programs. In the current study, a modified diet was formulated and assessed against two diets used for mass rearing of S. litura, and tomato fruits were taken as a natural diet. Results revealed that development attributes based on mass rearing of S. litura on the modified diet (wheat germ + tomato paste) significantly reduced the larval and pupal developmental duration by 30%, while, considerably enhancing eclosion rate, pupation survival rate, and the number of eggs by 20-30% along with the 40-50% reduction in the pupal and larvae mortality rate as compared to the tomato paste diet and chickpea diet. The rearing expenses for 200 larvae on the modified diet (674/Rs) were 2.5 folds less than the expenses for rearing the same number of larvae on chickpea based diet (1749/Rs.) and almost equal to the tomato paste-based diet (669/Rs.). Therefore, a modified diet based on wheat germ and tomato paste is suitable for mass rearing of S. litura for six generations for laboratory and field experimentation.