الفهرس 
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Abstract
This study was designed to evaluate the efficiency of alpha-cypermethrin, spinosad, Bacillus thuringiensis, chlorpyrifos and orange oil against the 2nd and 4th instar larvae of the cotton leafworm, Spodoptera littoralis, some biological aspects, and biochemical effect on the 2nd and 4th instar of this insect. As well as to study the side effects of tested materials on honeybee foragers. Chlorpyrifos was the highest toxic compound against 2nd and 4th instar larvae of the cotton leaf worm, recording LC50 = 1.14 and 1.239 mg/kg. Chlorpyrifos and B. thuringiensis were the most toxic compounds recording mortality % of larvae 53.33 and 50.0% for 2nd instar larvae. While, chlorpyrifos, spinosad and B. thuringiensis were the most toxic compounds for 4th instar larvae recording 50%. There were no significant differences between tested compounds and control in pre-pupal period, pupation%, pupal duration and pupal weight (g), adult emergence, sex ratio, longevity, the number of eggs/female, fertility of larvae, hatchability % and deformation% in 2nd and 4th instar larvae. Spinosad decreased amylase activity to 0.646 and 0.7284 µg/min/g after 24 and 48h. of treatment. Spinosad and orange oil increased enzyme activity to 87.477 and 89.286 µg/min/gm in 2nd instar larvae after 24 and 48h of treatment. Alpha cypermethrin increased trehalase activity to 169.675 and 176.33 µg/min/gm after 24 and 48 h of treatment in 2nd instar larvae. Spinosad increased Aspartate transferase activity 2nd instar larvae after 24 and 48h h from treatment, while, Alpha cypermethrin increased enzyme activity 4th instar larvae after 24 h from treatment. Spinosad increased Alanine transferase activity activity 2nd and 4th instar larvae after 24 and 48h h from treatment. Chlorpyrifos and B.T, increase the DNA fragmentation in both 2nd and 4th instar larvae samples. Chlorpyrifos was the most toxic tested compounds on honeybee foragers. In field experiment, Chlopyrifos recording the highest reduction% in the 4th instar larvae of cotton leafworm, S. littoralis at two seasons.