Monitoring rezistence Venturia Inaequalis k cyprodinylu a difenokonazolu v ČR v letech 2020–2022 [Monitoring of Venturia inaequalis resistance to cyprodinyl and difenoconazol in the Czech republic in 2020–2022]

Abstract

Apple scab, compared to other fungal diseases, consistently causes the most significant economic losses for growers. Venturia inaequalis infection not only reduce actual crop quality and quantity. Impaired tree vitality due to defoliation and a reduced number of buds in the following season are also the consequences of uncontrolled attack of apple trees by this fungal pathogen. Therefore the control of apple scab using fungicides is an essential part of the orchard life cycle. Knowing the sensitivity of local populations of V. inaequalis to active substances used in fungicidal sprays is a key factor for the sustainable protection of apple plantations against scab. In the years 2020–2022, V. inaequalis populations isolated from experimental and production orchards in the Czech Republic were tested for sensitivity to the active substances cyprodinil and difenoconazole. The assessment was carried out using in vivo tests on seedlings of the cultivar ‘Golden Delicious’. The monitored orchards showed the sensitivity to cyprodinil, where only two populations had reduced sensitivity. The majority of tested populations were also sensitive to difenoconazole. Only one population was found to be resistant to difenoconazole, and two populations were found to have reduced sensitivity to this agent. The results are consistent with similar foreign studies.

Keywords

• resistance
• apple tree
• sensitivity
• apple scab