Complex of Barley Leaf Spots in Ukraine

Abstract

Barley is one of the most important cereal crops globally. In Ukraine, it is grown on an area of 2.4–2.8 million hectares annually and is the second largest grain crop in Ukraine after wheat. Barley grain export is about 4.3 million tons p.a. At the same time, one of the limiting factors for obtaining a high-quality yield is diseases, in particular leaf spots. In recent decades, there have been significant changes in the technology of cultivation, the composition of varieties and the pathogenic complex. Net blotch (Pyrenophora teres Drechsler) in net and spot forms and spot blotch (Bipolaris sorokiniana Shoem.) remain the most common among the diseases of barley leaves. They occur in all regions where barley is grown. Barley scald (Rhynchosporium secalis (Oudem.) Davis) is distributed mainly in the forest zone and western part of the forest-steppe zone and has become more widespread in recent years with rainy summers. Outbreaks of stripe spot (Pyrenophora graminea S. Ito & Kurib.) occur sporadically. Ascochyta leaf spot (Ascochyta spp.) was found in the Lviv and Dnipropetrovsk regions in 2020, and in the Lviv, Donetsk and Zaporizhia regions in 2021. In the field, spots can be misdiagnosed as barley scald, so their prevalence may be much higher. In 2021, during the seed ripening period, ramularia leaf spot was found in the Kherson and Vinnytsia regions. The disease was diagnosed in the laboratory by obtaining a typical conidial sporulation of the fungus Ramularia collo-cygni B. Sutton & J.M. Waller on affected tissues (wet chamber). Therefore, in recent years, the composition of the barley leaf spot pathogens has become wider and requires further investigation.