Comparison of mosquito larvicidal efficacy between microbial encapsulated BTI (EBTI) and standard BTI (SBTI)

A comparative study was conducted on the efficacy of mosquito larvicides EBTI and SBTI. The results showed that: 1. The residual efficacy of EBTI was remarkably higher than that of SBTI at 0.007-0.002ppm BTI concentration (P < 0.01), the mosquito larvae mortality of EBTI remained 100% until the 4th week; in contrast, the mosquito larva mortality of SBTI gradually and obviously declined from the 2nd to 4th week after treatment (x2 = 8.17-24.08), and reached 0 at the 4th week. 2. The lowest BTI concentration of EBTI at which a high efficacy persisted for 4 weeks was 0.007ppm BTI, the mosquito larva mortality remaining 100%.