The Spectrum of Weed Phytopathogens in Wheat Agrophytocenosis.

Bacterial diseases, pests and weeds are the main factors that do not allow generating high yields of agricultural crops. The article presents the results of a study of agents of weed diseases. It was shown that the affected weeds in wheat agrophytocenosis present an ecological niche for phytopathogenic bacteria, belonging to the species Pseudomonas syringae, Pseudomonas viridiflava, Pseudomonas fluorescens, Pectobacterium carotovorum, Pantoea agglomerans, Xanthomonas translucens and Pseudomonas sp. In addition to these pathogens, phytopathogenic yeasts Rhodosporidium diobovatum and Rhodotorula sp. were isolated and identified. Most of the phytopathogens, isolated from weeds, are widely specialized and in experiment affect various species of weeds and cereals. Fatty acid composition of the total cellular lipids of these plant pathogens was identified and proved to be characteristic for each species of bacteria. P. syringae was determined as the main agent of bacterial diseases of weeds, its strains have a high degree of serological relationship to the agent of basal bacteriosis of cereals – P. syringae pv. atrofaciens and belong to the same serogroups. The results of RAPD-PCR analysis revealed that P. syringae strains isolated from weeds and disease agents of cereals present a genetically homogeneous group. The results obtained indicate that wheat and weeds are affected by the same agents of bacterial diseases.