Sensitivity of the North Caucasian and Belarusian populations of Microdochium nivale (Fr.) Samuels & hallet to fungicides

Abstract

Pink snow rot (pathogen Microdochium nivale) is the most common low-temperature pathogen worldwide. Sensitivity of two geographically distant populations of the pink snow rot pathogen (southern Russia and the Republic of Belarus) to nine modern fungicides was studied. The fungicides included in the State Catalogue of pesticides and agrochemicals permitted for use in the Russian Federation and recommended for treatment against snow rot were selected for the study. The material for the study was a pure culture of the fungus M. nivale. The agar block method was used in this study. The fungicide solutions were introduced into the nutrient medium using two standard methods: by interfering with the medium and by rubbing the preparation on the medium surface with a spatula. The preparations with 100% fungicidal effect against both studied populations were identified: Polaris, OE, Quinto Duo, SC and Bariton Super, SC. Oplot Trio, WS, Vybrance Trio, FC, Maxim Forte, SC showed 100% efficacy only against the Belarusian population of the pathogen. It was determined that the use of two methods of introducing the preparation into the nutrient medium (intervention and rubbing on the agar surface) has a high correlation coefficient (for the Belarusian population - rxy = 1.0, for the North Caucasian population - rxy = 0.99). However, intervention is less likely to inhibit colony growth and is therefore preferable in drug sensitivity studies of pure culture of the fungus M. nivale. A statistically significant difference was found between the sensitivity to fungicides of populations from geographically distant regions (Ft 5.32 < Ff 23.2 for the intervention method, Ft 5.32 < Ff 37.7 for the rubbing method). The data indicate the heterogeneity of the snow rot pathogen in terms of sensitivity to the modern assortment of seed dressing agents.