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Remarks (public):For a complete description including images see www.cababstractsplus.org/dfb 
Remarks (internal):It is generally a seed-borne fungus. On stored Sorghum seeds in India it caused significant reduction in root and shoot length and germination but produced no visible symptoms (59, 2159). Maximum inhibition of seedling growth in winter wheat and maize was caused by this fungus. The phytotoxic effect increased with the age of the fungus (57, 1670). Isolates from Agropyron repens in Canada infected all species of grasses tested (64, 5422). On green fruits of pawpaw it caused black circular spots 4-12 mm diam. (67, 5097). The fungicides thiram and verdasan compared with captan and dicloran were more inhibitory to growth and germination of D. biseptata in laboratory tests. Higher concentrations of fungicides also inhibited cellulose decomposition and starch hydrolysis (58, 2530).
 
Description type:Non-original description 
Description:Drechslera biseptata (Sacc. & Roum.) Richardson & Fraser, Transactions of the British Mycological Society 51: 148, 1968.
Helminthosporium biseptatum Sacc. & Roum., in Roum & Sacc., Rev. Mycol. 3: 56, 1881.
Helminthosporium biforme Mason & S. Hughes, in Chesters, Trans. Br. mycol. Soc. 30: 114, 1948.
Colonies growing rapidly, forming uniform dark grey to black, low, dense mycelia; margin light grey, forming numerous conidiophores and conidia. Conidiophores single or in groups from the substratum or in large fascicles from very dark brown pulvinate stromata, simple or branched near the base, of two kinds, erect to flexuous, thin-walled, pale to mid brown, geniculate, up to 80 um long, 3-8 µm wide, or subulate, dark brown, straight to flexuous, paler towards the apex, up to 800 µm long, 10-14 µm wide. Conidiogenous nodes verruculose. Conidia obovate to broadly clavate, occasionally ellipsoidal, pale brown to mid brown, smooth to verrucose, 2-3-distoseptate, 16-42 x 9-19 µm; germination by one to three germ tubes from the basal cell and rarely from apical and central cells.
Hosts: Agropyron, Aira, Avena, Dactylis, Hordeum, Microlaena, Sorghum, Tetrarrhena, Triticum, Vulpia and Zea; also isolated from Carica papaya (67, 5097).
Disease: Seed-borne, fruit rot of papaya.
Geographical distribution: Australia, Europe, India, New Zealand, North America.
Physiological specialization: None reported.
Transmission: Wind-borne conidia, seed-borne (59, 2159).
Literature: Ellis, Dematiaceous Hyphomycetes, p. 418, CMI, 1971; Prasad, Sinha, Shankar & Kumar, Indian Phytopathology 39: 493, 1986; Rani, Mohan & Mukerji, Seed Research (New Delhi) 6: 38-42, 1978; Sampson & Watson, Canadian Journal of Plant Pathology 7: 161-164, 1985; Sivanesan, Mycological Papers 158: 1-261, 1987.
 
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