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 LC 50 and LC 90 values, chlorpyrifos was the most effective insecticide that recorded 0.1 and 0.809 ppm for 2 nd instar larvae and 0.472 and 6.838 ppm for 4 th instar larvae, respectively. Meanwhile, tebufenozide appeared to be the least effective compound against both tested instars that gave 9.901and 36.447 ppm against 2 nd instar, whereas the LC 50 and LC 90 values were 65.736 and 1000.775 ppm) against the 4 th 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 4 th 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.

Field and laboratory trials were conducted in Zagazig -Sharkia Governorate during 2007 and 2008 cotton seasons to evaluate the efficacy of emamectin benzoate (against cotton leafworm Spodoptera littoralis and pink bollworm Pectinophora gossypiella.Emamectin benzoate resulted in initial kill of 93.73 and 92.39 % reductions in the numbers of cotton leafworm Spodoptera littoralis, larvae, comparing with 98.22 and 95.93 % for the recommended IGR hexaflumuron (Consult) (while as the residual effect emamectin benzoate revealed to 83.69 and 82.35% reductions comparing with 95.07 and 93.93 % for the hexaflumuron, in 2007 and 2008 cotton seasons, respectively. The efficiency of emamectin benzoate in comparison with the recommended insecticide chlorpyriphos (Dursban) against cotton bollworm, pink bollworm, Pectinophora gossypiella, they resulted in 59.40 and 54.68% for emamectin benzoate, and 81.81 and 83.21% for chlorpyriphos as average seasonal reductions, during the two cotton seasons, respectively. Laboratory trials revealed that LC50 and LC 90 of emamectin benzoate were higher with cotton leafworm than pink bollworm, which were 2.783 and 1.656 ppm at LC 50 , while they were 29.096 and 11.193 ppm at LC 90 , respectively. The slope value of emamectin benzoate with cotton leafworm was 1.257 less than with pink bollworm which recorded 1.544.

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Side effect of six Insect Growth Regulators (IGRs) (lufenuron, teflubenzuron, flufenoxuron, chlorfluazuron, methoxyfenozide and chromafenozide) used against the cotton leafworm, Spodoptera littoralis (Boisd.) in cotton field was studied on Coccinellidae spp, Chrysoperla carnea and true spiders predators under field conditions during 2013 and 2014 cotton seasons. The obtained results showed that the numbers of all tested predators were decreased after three days of IGRs application and return to increase after seven days in the two seasons. Chlorfluazuron was the most toxic against all tested predators. The percent efficacies of Chlorfluazuron were 37.07, 33.60 and 24.90% for Chrysoperla carnea, true spiders and Coccinellidae spp, respectively. While, flufenoxuron (13.89%), teflubenzuron (22.60%) and methoxyfenozide (22.13%) were the lowest toxic against Coccinellidae spp. C. carnae and true spiders, respectively. These results recommended that chlorfluazuron was not suitable during the peak of natural enemies.