FIELD: biotechnology. SUBSTANCE: invention relates to preparing biological agents used for plant protection. Plant resistance inducing agent is extracted from fungus Sclerotinia sclerotiorum cultural fluid. Fungus is cultured by submerged method in liquid nutrient media containing mineral and organic components. Cultural fluid containing an exogenous inducing agent is separated from the formed mycelium by centrifugation and purified on anionite, for example, APA-2p. Obtained centrifugate is sorbed on solid sorbent, for example, activated carbon followed by desorption with organic solvent dimethylsulfoxide. Sorbent is washed out with acetone or chloroform and dimethylsulfoxide is frozen out from obtained mixture at minus 20 C and then inducing agent is isolated by filtration on glass porous filter followed by its concentration and evaporation at plus 40 C by 100-fold. Values of immune response in biotesting assay with inducing agents obtained from fungus cultural fluids grown for preparing each inducing agent in definite nutrient medium for sunflower and cucumber seeds are determined to be 32.8-62.2 % and 29.3-60.3 %, respectively. In field experiments of sunflower seeds treated with inducing agents obtained from fungus cultural fluids grown for preparing each inducing agent in definite nutrient medium per cent of damage of sunflower roots by white rot is determined to be 20-29.1 %. EFFECT: improved method of inducing agent preparing. 6 cl, 2 tbl, 7 ex
