The larvicidal activity of Bt israelensis on mosquito transmitted diseases was the most important feature of the strain.
The insecticidal properties of this bacteria are due primarily to insecticidal proteins produced during sporulation. The key proteins are Cyt1A(27.3·kDa), Cry4A (128·kDa), Cry 4 B (134·kDa) and Cry11A (72·kDa) and in three different inclusion types assembled into a spherical parasporal body held together by lamellar envelope (Ibarra & Federici, 1986). The inclusions are realtively small (0.1 to 0.5m) and there are usually two to four inclusions per cell which vary in shape from cuboidal to bipyramidal, ovoid or anamorph (Charles & de Barjac 1982; Mikola et al. 1982; Yamamoto et al. 1983)