Scientific Journal of KubSAU

The purpose of the work was to test the winter wheat varieties artificially infected with North-Caucasus brown rust to identify its harmfulness. There was carried out a two-stage testing on two sets (8 and 10) of varieties that differed in their resistance to the pathogen. As a result, there has been identified high brown rust harmfulness in susceptible varieties, which led to a yield decrease from 16.3 to 32.2%. Among the maximum infected varieties, there has been identified the most tolerant variety ‘Tarasovskaya 29’ which, when damaged to 100%, had a minimum yield decrease (less than 10.6%). The poorly susceptible to brown rust varieties reduced their yields from 11.2% to 20.7%. Among them, the variety ‘Spartak’ showed lower rates of a yield decline. Among the five varieties that showed an average brown rust affection, there have been noted various indicators of a yield decrease. The variety ‘Donskaya Yubileynaya’ showed a minimum decrease of a yield and its structural elements under the conditions of artificial infection with brown rust; and together with the variety ‘Tarasovskaya 29’ can be classed to the varieties tolerant to brown rust. When predicting brown rust epiphytoty the susceptible and medium-resistant wheat varieties require obligatory protection with fungicides