EVALUATION OF THE LARVICIDAL ACTIVITY AND EFFECT ON PROTEIN CONFIGURATION OF TWO BACILLUS SPECIES AND SIX PLANT EXTRACTS TESTED AGAINST CULEX PIPIENS AND AEDES CASPIUS LARVAE

All tested bacteria and plant extracts proved larvicidal activity against third instar larvae of both mosquitoes Culex pipiens and Aedes caspius .Bacillus sphaericus, indigenous strain (dammam) showed higher activity against Cx. pipiens larvae, with LC50 = 0.35x10-7 ppm. Than to Ae. caspius (LC50= 4.5x10-7 ppm) .Bacillus thuringiensis H-14 (Bactimos) has higher toxicity against Ae. caspius, followed by Cx. pipiens (LC50=8.0x10-7 and 1.4x10-6 ppm respectively. Both mosquito larvae were susceptible to all tested native plant extracts, Cleome arabica, Fagonia mollis, Gomphocarpussincaicus, Origanum syriacum, Trichodesma africanum and Artemisia judaica with median lethal doses equal to 125.09, 135.1, 203.03 , 289.5, 310.8 and 450.08 ppm when tested against Ae. caspius larvae and 225.07, 188.2, 305.5, 390.4, 420.2 and 650.2 ppm when tested against C. pipiens larvae. All treatments led to protein disconfiguration of treated larvae. Fractionation of native proteins, disappearance of some peptides and appearance of new bands are signs obviously recorded after larval treatment with the tested microbial agents or plant extracts.