ALUMINUM CARBOXYMETHYLCELLULOSE ENCAPSULATION OF BACILLUS-SPHAERICUS-2362 FOR CONTROL OF CULEX SPP (DIPTERA, CULICIDAE) LARVAE

Bacilllus sphaericus 2362 spore-toxin complex was encapsulated within aluminum carboxymethylcellulose (CMC) and assayed for larvicidal activ ity against 2nd and 3rd instars of Culex spp. to determine the release properties of the system. Encapsulation of the bacterium exhibited hi gher stability toward acidic pH, temperature (50 degrees C), and UV ir radiation (12 W). The stability of spore-toxin viability detected for the encapsulated pathogen was higher than that for the free bacterium, because the procedure prevented the bacterium from being faced direct ly with microbial degradation, W and sunlight, temperature, and pH var iations. Mortalities in treatments involving incorporation of encapsul ated B. sphaericus 2362 into artificial diet of Culex spp. larvae were observed starting from the 48th h after inoculation. Aluminum sulfate (0.05 M) and 1% sodium CMC concentrations were found to be optimum, b ecause higher gellant and polysaccharide levels caused slower release of the bacterium. Our results suggest that the aluminum CMC-encapsulat ed form of B. sphaericus 2362 can be used more efficiently than its fr ee form in the control of mosquito larvae.