The stomach poisonous impact of some insect growth regulators and biocides was tested under laboratory and semi-field conditions against cotton leafworm, S. littoralis. Obtained results revealed that, the second instar larvae reflected higher level of susceptibility towards all the tested insecticides than fourth one. According to LC50 and LC90 values, chlorpyrifos was the most effective insecticide that recorded 0.1 and 0.809 ppm for 2nd instar larvae and 0.472 and 6.838 ppm for 4th instar larvae, respectively. Meanwhile, tebufenozide appeared to be the least effective compound against both tested instars that gave 9.901and 36.447 ppm against 2nd instar, whereas the LC50 and LC90 values were 65.736 and 1000.775 ppm) against the 4th one, respectively. The rest compounds gave moderate effects in this respect. Data concerning the initial and residual activity of the tested insecticides, Tracer, XDE, methoxyfenozide, Dipel 2x and chlorpyrifos against 4th instar larvae of field strain cotton leafworm, S. littoralis were determined. The initial effect calculated as the cumulative mortalities at zero time recorded 100, 100, 92, 88 and 26 % for methoxyfenozide, chlorpyrifos, XDE, Tracer and Dipel 2x, respectively. The untreated check recorded 2%, methoxyfenozide and chlorpyrifos gave the highest significant mortalities effects comparing to the untreated, Chlorpyrifos and methoxyfenozide were detected the highest significant mortalities effect as general residual effect whereas Dipel 2x recorded the least significant mortality effect, which it being 18.40% as compared to other insecticides.