DYNAMIKA REZISTENCE POPULACÍ VENTURIA INAEQUALIS KE STROBILURINOVÝM FUNGICIDŮM [DYNAMICS OF RESISTANCE OF VENTURIA INAEQUALIS POPULATIONS TO STROBILURIN FUNGICIDES]

Abstract

Venturia Inaequalis, the causative agent of apple scab, is an important pathogen whose presence in orchards has far-reaching economic consequences for growers, whether it concerns the management of fungicides or financial loss by fungicide-management failure. Therefore, monitoring of the resistance to used fungicides in V. inaequalis populations is advisable. Strobilurins are one group of substances used in the protection against scab acting by blocking the respiratory chain. Resistance to these substances is mediated by a point mutation in one of the components of the electron-transport chain of cytochrome b, in the cytb gene, which can be detected by the real-time PCR method. Using this method, the percentage of the mutated variant of the gene is determined, therefore whether the population is sensitive or resistant to strobilurins. The rate of population resistance was monitored for 5 years in 11 locations with different regimes of protection of apple trees against scab. Sites with a history of strobilurin use maintained high rates of resistance in the population, which continued to rise after treatment was quit. Localities where strobilurins were not applied for a long period gradually reduced the proportion of the resistant gene, roughly by one percent per year. Due to the maintenance of a high percentage of the resistant cytb allele in the population, where the selection pressure using strobilurins has not been used for at least 5 years, it is necessary to highlight the necessity of rigorous adherence to anti-resistance strategies.

Keywords

• qo inhibitors
• rezistence
• venturia inaequalis
• real-time pcr