Habit characteristics of imperfect and perfect stage of D. bryoniae encountered on naturally infected seeds of cucumber and pumpkin were studied by the blotter method and compared with those grown on Difco potato dextrose agar, v-8 juice agar and Water Agar Leaf Medium.
Most of the pycnidiospores obtained from each isolate of this fungus grown on PDA were nonseptate and microtype. Non-septate pycnidiospores were predominanted in all isolates, but a macrotype of the non-septate and a number of uniseptate pycnidiospores were produced on V-8 juice agar and Water Agar Leaf Medium.
On seed the pycnidiospores were mostly nonseptate, but rarely uniseptate ones were also found. On radicle of cucumber seed, the pycnidiospores were non-septate and uniseptate but small percentage biseptate with somewhat constricted at septa. Pycnidiospores produced on V-8 juice agar and Water Agar Leaf Medium were similar to those produced on seeds.
In the present investigation the perithecia were mostly globose to subglobose with apical papillate ostiole and whitish spore masses formed on the ostiole of perithecia, either on naturally infected seed or on culture media. The mature perithecia were dark brown to black. They were partially embedded or erumpent on seed coat and culture media. The perithecia varied in size within a much narrower range than the pycnidia. But perithecial formation of this fungus on PDA, v-8 juice agar, WALM and seed varied considerably depending upon isolate and substrate.
|