Evaluación de dos formulaciones de Bacillus thuringiensis H-14 para el control de larvas de Aedes aegypti

Abstract

Two formulations of Bacillus thunngiensis H-14 were tested in the laboratory and field against Aedes aegypti larvae, a wettable powder (3.500 ANl) and liquid concentrate (1.000 AMI) (AA= Intemational A. aegypti Toxic Units). The laboratory tests were carried out with four different dosages of each formulations. The LD 99.9 was found. Residual action did not increase in direct proportion to the dosage. At a dose of 1,050 AA/l the residual-aciion was found to be 11 days for the wettable powder and 9.9 days for liquid concentrate. Daily adult emergence, as measured by retumig to 30% of pretreatment levels, was delayed 21.7 days when the wettable powder was applied and 18 days when the liquid concentrate. Daily adult emergence, as measured by returnig to 30% of pretreatment levels, was delayed 21.7 days when the wettable powder was applied and 18 days when the liquid concentrate was applied. Although statistically significant differences were found between different dosages and types of breeding containers, these differences have no operational importante. The field trials were done by appling a dose of 1.500 AA/1 to laundry tanks, drums and tires. A residual action against larvae of 9 days was obtained with the wettable powder and 7.2 with the liquid concentrate. B.t. H-14 was shown to be effective against all larva1 stages of A. aegypti in the breeding containers treated. Its use as an alternative larvicide has possibilities in special situations where chernical methods are undesirable or where other control method are not practical.