Fig. 2

Symptom development of C. rhododendri-infections over time of PRA-A (representative of susceptible genotypes) and of the resistant genotype PRA-R needles. At 18 dpi, first symptoms of infection were detectable under the microscope, i.e., small blisters on the needle surface become visible on symptomatic (S) needles while other needles remained non-symptomatic (NS). At 38 dpi, several current-year needles of susceptible trees showed a characteristic yellow discoloration and first aeciospore stocks were formed, while PRA-R was only slightly affected, with tiny yellow spots on S needles (arrows indicate symptoms)