Inter-Specific Host Hybrids and Phalacrid Beetles Implicated in the Local Survival of Smut Pathogens

In populations of the sedges Carex canescens and Carex mackenziei, the incidence and severity of a non-systemic floral smut fungus, Anthracoidea fischeri, was strongly associated with the occurrence of natural hybrids. Data from 23 localities showed that in the presence of the hybrid (13 localities), both parents sustained infection while in its absence (10 localities), both were disease-free. Furthermore, in mixed populations of parental and hybrid plants, the incidence and severity of disease was always much greater on hybrid than parental plants (5 to 9 and 30 to 80-fold, respectively), and parental plants were more often diseased when growing close to hybrid plants. Hybrids were earlier regarded as completely sterile, however, we obtained successful germination of hybrid seeds from two localities (...)