Pathocomplex of root rot of apple tree in nurseries and young orchards of the South of Russia

Abstract

Root rot poses a serious threat to the main fruit crop domestic apple in nurseries and young orchards. Obtaining healthy planting material, free from root pathogens and root rot, is an especially priority task in conditions of intensive production. In the process of analyzing the affected plants from nurseries and young orchards at four sampling points, pathogens of apple root rot from 11 genera were identified and 431 isolates were extracted. The most common causative agents of apple root rot seedlings in the entire studied sample were species of the genus Fusarium spp. Soil micromycetes such as Rhizoctonia spp., Cladosporium spp., Cylinrocarpon spp., and oomycetes from the genus Pythium were rare. The composition and occurrence of species were heterogeneous at different points in the studied region. Phomopsis mali (Schulzer & Sacc.) Died., Cytospora spp., Alternaria alternate (Fr.) Keissl., and Aspergillus niger Tiegh. have been associated with root rot of seedlings and young apple trees.