Questions concerning studying entomocyde (entomotoxic), larvicidal activity of various biovariants (serotypes) Bacillus thuringiensis (BtH1, BtH10, BtH14), differing among themselves by specificity, multilateral action concerning a wide range of hosts-insects and the raised potential of activity for creation bioinsecticides as reliable supervising means of number of target objects are considered. High biological activity strains Bt ssp is established. So, entomocyde BtH1, BtH10 for L1-2 Leptinotarsa decemlineata Say. - 0,19 % CB; and the maintenance exotoxin - 2,5-2,8 mkl/g a forage for L2 Musca domestica. Larvicidal activity BtH14 in limits 0,15х10-3 % CB for L4 Aedes aegypti. The age susceptibility of insects to action entomotoxins Bt is noted.