Phytopathogenic micromycetes of oats under the conditions of the Irkutsk region

Abstract

   The results of phytopathological examination of grain batches of oat zoned varieties Rovesnik and Egorych grown in different areas of the Irkutsk region and harvested in 2015-2016 and in 2020-2021 have been presented. Infestation with micromycetes was determined by the wet chamber method according to GOST 12044-93. The weather conditions during the growing years of the examined oat batches were warm and characterized by a deviation of moisture during the growing season from the norm which led to plants weakening and the reinforced development of phytopathogenic  micromycetes. A high ubiquitous occurrence of fungi from the genus Alternaria has been established. In 2015 the infestation of oat cultivar with Rovesnik fungi from the genus Alternaria ranged from 20 tо 36 %, and that grown in 2016 – from 44 tо 83 %. The variety Egorych in 2016 was infested from 43 tо 91%. In the batches harvested in 2020 and 2021, irrespective to a cultivar, the infestation was from 70 tо 100 % and from 60 tо 98 %, correspondingly. Bipolaris spp. was observed in all the analyzed batches of oat variety Rovesnik in the harvests of 2015 and 2016 with a varying infestation range of 3-12 % and 4-37 %, respectively. The cultivar Egorych harvested in 2016 had the infestation level from 3 tо 87 %. In the harvests of 2020 and 2021, single batches free from Bipolaris spp. were found, but most of them had a degree of infestation, regardless of a variety, of 7-40 % and 3-45 %, respectively, in 2020 and 2021. The occurrence of phytopathogens of the genus Fusarium spp. did not depend on the variety, but it differed greatly in years. In the grain of most batches harvested in 2015-2016, the infestation with micromycetes Fusarium spp. was within the range of 1-24 %, and in the harvest of 2020-2021 the batches with very high infestation with this pathogen prevailed – 23-93 % and 20-67 %, respectively. Single batches were free of Fusarium spp.