In vitro evaluation of effect of new fungicides against yellow spot (pyrenophora tritici-repentis) of wheat

In response to the producers' concerns about reducing the cause of wheat yield loss from the necrotrophic pathogenic fungus Pyrenophora tritici-repentis, which informed the purpose of this study, to investigate the effectiveness of fungicides in reducing the prevalence of yellow spot during artificial infection in the field conditions of the Republic of Dagestan and the Rostov region. The experimental design included: T1) Taxis, SC (240 g/l azoxystrobin + 160 g/l epoxiconazole) (0.5 l/ha); T2) Taxis, SK (0.6 l/ha); T3) Spirit, SC (240 g/l azoxystrobin + 160 g/l epoxiconazole) (standard) (0.6 l/ha); and T4) Control (without treatment). On control plots, the prevalence of yellow spots corresponded on average to 32.5% (Homer) and 37.2% (Grom) for winter wheat varieties and 32.6% (Malachite) as well 35.7% (Prokhorovka) for spring wheat varieties respectively. At the same time, the smallest disease prevalence was observed in the treated variants T1, T2, and T3, on average 2.6–6.5%. Furthermore, the effective protection of the leaf surface during the 2-fold treatment of wheat crops with fungicides led to an increase in yield in both study regions from 11 to 19%.