Development and species composition of septariosis in crops of spring triticale varieties in Belarus

Septoria leaf and head blotch is the most economically significant disease of grain crops in Belarus, as it is annually observed in crops and is highly harmful. Spring triticale is a perspective crop in our country with a high yield potential and grain quality, which, as known, decreases due to diseases development. There is little information on the varieties disease susceptibility, development peculiarities and species composition of septoria blotch of spring triticale, which determined the relevance of our research subject. The paper presents the results of studies in 2015-2019 on susceptibility of spring triticale varieties Uzor, Doublet, Sadko to septoria leaf and head blotch, peculiarities of the disease development depending on weather conditions were revealed and the species composition of pathogens of septoria leaf blotch was determined. It has been determined that severity of septoria leaf blotch by the end of early – soft dough of grain stage reached 36.6 %. Based on calculation of area under the disease progress curve, no significant differences were found in severity of septoria leaf blotch depending on the variety. Severity of septoria head blotch reached 22.7 % by the end of growing season. Direct dependences of septoria leaf and head blotch development on the amount of precipitation have been established, and a close correlation between the severity of septoria head blotch and septoria leaf blotch has been revealed. The species composition of septoria leaf blotch is represented by the fungi Parastagonospora nodorum, Parastagonospora avenae f. sp. triticae and Zymoseptoria tritici. The dominant species was P. nodorum, its frequency reached 99.2 % depending on the variety and growth stage of spring triticale, the second most common fungus was P. avenae f. sp. triticae - up to 58.6 %. For the first time in our country, in-depth research has been carried out to study septoria leaf and head blotch of spring triticale, the results obtained will serve as the basis for development of a protection system.