Leaf rust caused by Puccinia recondita Rob. ex Desm. f. sp. secalis is the most important windspread pathogen in rye and is endemic in all rye growing regions. Epidemic incidence of leaf rust has potential to result in distinct yield reduction. Under natural infection yield losses were reported to mount up to 40 % under continental climate conditions.

Main symptoms
Small  brown  pustules develop on the leaf blades and may group into patches in serious  cases. Onset of the disease is slow but accelerated in temperatures above 15 °C. Symptoms can range in severity from barely  aesthetic  to completely overrun on the leaf surface.

Genetic Disease Prevention
Genetic analysis of resistance to leaf rust in rye led to the identification of resistance genes. The cultivation of resistant cultivars contributes to a sustainable agriculture.