| Abstract: | The relative susceptibility of Melampyrum arvense, M. pratense, M. sylvaticum and M. nemorosum to Cronartium flaccidum was investigated by artificial inoculations. Uredinia and telia were artificially produced on plants from sown seed or transplanted from the wild in the greenhouse. This is the first report in which C. flaccidum telia were artificially produced on leaves of whole plants of M. arvense and M. pratense, the first report of successful artificial disease establishment on M. arvense and the first report of telia production on the upper surface of Melampyrum leaves. As an earlier unreported observation, telia were occasionally formed on both upper and lower leaf surfaces of M. arvense, M. sylvaticum and M. pratense. Host species, spore source and their interaction each affected some aspects of disease development. Melampyrum arvense and M. sylvaticum were the most susceptible hosts, while M. nemorosum was least susceptible. Melampyrum arvense should be considered a potentially important alternate host of C. flaccidum with its limited area of distribution. |
