The cotton leafworm (CLW), Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae), and the fall armyworm (FAW), Spodoptera frugiperda (JE Smith) (Lepidoptera: Noctuidae), inflicting significant economic harm by consuming the majority of Egypt's crops. An economical, semi-artificial diet devoid of agar was required to facilitate ongoing biological study on these pests to mitigate their expansion. The survival parameters of the two pests were analyzed during three successive generations on a standard diet of fresh castor bean leaves, Ricinus communis L., and a novel experimental diet. Acquiring data that effectively substantiates the technique will facilitate its development into a feasible strategy for managing pest lepidopterans. The expense to grow 1000 newly hatched CLW and FAW larvae to the pupation stage using artificial feeding components is 33 L.E., around $0.70. This is approximately 80% more economical than agar-based alternatives. This technique facilitates future research on more cost-effective gelling chemicals for growing lepidopteran insect pests, hence simplifying the study and manipulation of these insects