Alternaria of ornamental, fruit and berry crops

The aim of the study was to assess the development and distribution of fungi of the genus Alternaria Nees on plants from various families of ornamental, fruit and berry crops. The collection and analysis of the samples was carried out in Moscow and a number of regions of the European part of Russia (Moscow, Kaluga, Tula regions, Stavropol Territory, Republic of North Ossetia, Chechen Republic) during 2018-2020. In all studied regions, Alternaria was recorded among tree crops of 11 families: Actinidiaceae Gilg & Werderm., Betulaceae Gray, Cornaceae Bercht. & J. Presl, Juglandaceae A. Rich. ex Kunth., MagnoliaceaeJuss., MalvaceaeJuss., Moraceae Gaudich., Oleaceae Hoffmanns. & Link, Rosaceae Juss., Sapindaceae Juss., Vitaceae Juss. The causative agent is fungi of the genus Alternaria. Microscopic examination revealed the following types of Alternaria pathogen (mainly parasites with necrotrophic nutrition) on tree crops: A. tenuissima Nees, A. alternata (Fr.) Keissl. and A. infectoria (Fuckel) M. E. Barr & E. G. Simmons. The strongest level of distribution (P, %) of fungi of the genus Alternaria was recorded on Crataegus submollis Sarg., 92-95 %, with a disease development rate of 38-42 % (R), Syringa vulgaris L. and Tilia cordata Mill. (P = 90 % and R = 21-22 %). A. tenuissima has a wide range of host plants among fruit and berry crops. Among the 24 species of major dicotyledonous weeds identified in the study areas are Aegopodium podagraria L., Convolvulus arvensis L., Malva pusilla Sm., Sonchus arvensis L. A. tenuissima and A. infectoria have been identified (R from 10 to 25 %, P=100 %). these types of dicotyledonous weeds can be an additional source of spreading the pathogen alternariosis to fruit and ornamental plants.