Biocidal and resistance-inducing effects of chitosan on phytopathogens

In connection with the of law adoption on organic products in Russian Federation, as well appearance fungicide-resistant forms phytopathogens, search for new preparations biological origin plant protection from disease remains relevant. Chitosan is a promising substance obtained shells crustaceans, zygomycete fungi: one hand, it prevents pathogen's penetration into inducing horizontal resistance, and other, has bactericidal effect against some bacteria fungi. This article shows biocidal chitosan hydrolysate molecular weight main fraction 33.7 kDa relation to 5 phytopathogenic bacteria. The minimum concentration ranged 0.25 0.5%. It was noted that acts more actively Gram-negative than Gram-positive. Biological efficacy artificial infectious background cucumber downy mildew during preventive treatment amounted average 55.4% compared control no treatment.