Entomocide character of Bacillus thuringiensis activity was discovered by L. Pasteur at the last half of XIX already. Several insecticide substances was designed on the base of this bacterial species at our country (bitoxybacillin, lepidocid, dendrobacillin) and abroad. Active parts of the bitoxybacillin (BTB) are -exotoxin (-ET) and crystal -endotoxin. The former one is the adeninnucleotide, the later one is the protein crystal. It was shown the existence of the additional active substance appointed to entomocide metabolite (EM) as proposed the nature chemically near to -ET. Biological activity of the entomocide substances and derived active parts such as -ET and EM upon seedlings plants was investigated. The results are as follows: 1.Exotoxins (-ET and EM) suppressed wood (Pinus sylvestris, Larix Gmelinii) and Pisum sativum seedlings growth. They induced the diminish of plant wet weight and inhibited the seed energy of plant growth initiation. 2.Seedlings development under BTB and lepidocide commercial substances, exotoxins of BTB exposition followed by changes at pigment apparatus. 3.Photosynthesis of seedlings exposed by exotoxins was lower against the control.
