The fall armyworm "Spodoptera frugiperda" is the most notorious insect pest distributed throughout the world's maize-growing areas. S. frugiperda has become threatening a sector of agricultural productivity attributed to its highly invasive characteristics. Nowadays, there is a trend to use eco-friendly insecticides for the management of these pests. In the present study, the 2^nd instar larvae of S. frugiperda were exposed to series concentrations of three insecticides "Bacillus thuringiensis subspecies Kurstaki (Btk, 6.4% wettable powder) and emamectin benzoate (5% soluble granules) as bioinsecticides, and lufenuron (5% emulsifaible concentrates) as an insect growth regulator" to evaluate the median lethal concentration (LC₅₀) values, and to study their impacts on biological and biochemical aspects of insect in a laboratory assay. The results exhibited that LC₅₀ values of Btk, lufenuron, and emamectin benzoate were 0.2999, 0.2722, and 0.0005 ppm, respectively. Also, exposure of S. frugiperda to LC₅₀ values of the tested insecticides altered significantly some biological aspects. Larval mortality raised significantly in S. frugiperda treated with LC₅₀ of all used insecticides compared with the control group. The biochemical response of S. frugiperda larvae against the insecticides lowered the mean values of carbohydrates and proteins compared with the control group; besides the digestive enzymes of S. frugiperda larvae exhibited significant reduction too. The activity of phenoloxidase, acetylcholinesterase, glutathione S-transferases, and chitinase were significantly varied at the LC₅₀ levels of the insecticides. In conclusion, all used insecticides were efficient, and can be recommended to control the fall armyworm, and is a promising alternative to conventional insecticides.