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DEVELOPMENT OF POWDERY MILDEW (ERYSIPHE POLYGONI) ON SUSCEPTIBLE AND RESISTANT RACES OF OENOTHERA BIENNIS
Author(s) -
Dickey Jean L.,
Levy Morris
Publication year - 1979
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1979.tb06329.x
Subject(s) - powdery mildew , biology , spore , haustorium , inoculation , evening primrose , appressorium , botany , fungus , germination , horticulture , host (biology) , ecology , food science
Races of Oenothera biennis (evening primrose) resistant and susceptible to Erysiphe polygoni (a powdery mildew fungus) were artificially inoculated with E. polygoni and the time course and mode of disease development recorded. This study was the initial stage in investigating the host's resistance mechanism(s). On leaves of susceptible and resistant races, spores germinated within 5 hr, appressoria were formed in 8‐12 hr, and penetration had been effected and haustoria initiated by 20 hr. There was no further development on resistant plants. On susceptible hosts, secondary penetration occurred by 26 hr after inoculation, secondary haustoria were formed, and sporulating colonies were seen in 4 days. It was concluded that the fungus is unable to establish a feeding relationship with the epidermal cells of resistant Oe. biennis , marking the period between 20 and 26 hr after inoculation as the time frame for the manifestation of the resistance mechanism(s).