Potato tolerance

Potato tolerance or field resistance is evaluated on a 9-point scale, where 9 points indicate the absence of symptoms and 1 point indicates near-complete destruction of the haulm or tubers. Intermediate values (5 points) are determined when 25–50% of the plant area is affected, which allows for classifying the variety based on its ability to withstand disease pressure.

Observations of tolerance are conducted during epiphytotic years in a dynamic manner at intervals of 6–10 days following the emergence of primary disease foci, with separate consideration given to tuber infection at harvest. A high level of tolerance allows for reduced pesticide load by increasing intervals between fungicide applications up to 14 days and minimizing yield losses under adverse weather conditions.