The efficiency of Chlorypyrifos, Jojoba and Diplel DF against 2^nd and 4^thinstars of the laboratory strain of Spodoptera littoralis was evaluated under laboratory conditions Chlorypyrifos was the most toxic compound against the 2^nd and 4^th larval instars of Spodoptera littoralis. All the treated larvae were biologically affected by the three tested compounds. The effect was varied according to the larval instars and tested compounds. Therefore, the treated larvae have resulted in decreased pupation and adult emergence percentages, and the 2^nd instar treated with Chlorypyrifos had the strongest effect in this respect. The treatment of 2^nd instar with the three compounds induced the highest increase in larval, pupal duration and adult emergence percentages.
           Hence, the larval treatment of 2^nd and 4^th instars with Chlorypyrifos and Diplel DF gave the shortest period of adult longevity, as compared to control. The larval treatment of 2^nd and 4^th instars with the three tested compounds increased the adult emergence, the treatment of 2^nd instar with Chlorypyrifos and 4^th instar with Diplel DF had the strongest effect in this respect.