Podbel’skogo, St. Petersburg, 196608 Russia, e-mail t.gagkaeva@mail.ru Acknowledgements: Supported by grant of Russian Science Foundation, project ¹ 14-16-00114 A b s t r a c t The composition of plant and silage microflora affects the fermentation processes in the silage and its final quality. <...> To date, reports about studying fodder plants and silage microbiota by means of molecular genetic methods are few and limited to descriptions of composition and function of some groups of microorganisms. <...> Moreover, the NGS (next generation sequencing) data on diversity of epiphytic microflora and silage microbiocoenosis are not still reported. <...> We first used this approach in studying phyllosphere and silage microbiom, and reported it to be rather rich in composition and abundance that is in contrast with conventional understanding. <...> At that, the pathogenic and non-culturable microbes were detected in the microbiota, including specific inhabitants of mammalian gastrointestinal tract. <...> So using NGS we examined the structure and diversity of bacterial community of L. harvested plants and the biomass ensilaged with chemical preservative AIV 2000 Plus (KEMIRA OYJ Inc., Finland) composed of mixture of formic, propionic and benzoic acids. <...> Assays were carried out on days 3, 7, 14 and 30 of ensilaging. <...> The results showed that the bacterial community of silage from sharply differed from the composition of foliage microorganisms and varied greatly in the course of successive changes which occurred during maturation of silage preserved by mixture of organic acids. <...> The composition of plant microorganisms and silage were found to be very various in contrast with a traditional view. <...> Among foliar microorganisms of phylum (94.1 %), and in the silage the bacteria of phylums of the order 39.6%), the family phylum (up to 36.36 %), were main representatives (up to 59.5 % and 74.9 %, respectively). <...> Interestingly, in the silage there were the bacteria of , and , considered the common inhabitants of the mammals’ gastrointestinal tract, and also the uncultured and pathogenic microorganisms. <...> Classical microbiology methods are not enough to detect these bacteria among silage microbiota. <...> Silage microbiocenosis is formed of epiphytic microorganisms present on forage crops. <...> Modern molecular techniques complement classical identification methods in microbiology [2-6]. <...> To date, the reports on fodder plant and silage microbiota studies using molecular genetic methods are few and limited to the descriptions of composition and function <...>