[The phage sensitivity and insecticidal activity of local strains of Bacillus sphaericus]

The sensitivity of 132 local isolates of B. sphaericus to phages 3, 4 and SST of A. Yousten has been studied. According to this incomplete phage typing, most of the strains are classified in the third phage group. A high-degree correlation between sensitivity to phage 4 and insecticidal activity was established, owing to which this sensitivity can be used as an initial criterion for selection of newly isolated strains. LC50 and LC90 of one reference and six local strains of B. sphaericus were determined using Culex pipiens third instar larvae, and the local strains were found to exceed in insecticidal activity the reference strain 2362. This suggests that the newly isolated strains are promising for developing of a preparation for biological control of mosquitoes.