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Remarks (public):For a complete description including images see www.cababstractsplus.org/dfb 
Remarks (internal):Fusarium culmorum is one of the most stable and uniform species of Fusarium although mutants do occasionally occur and these generally show a reduction in pigmentation. No perithecial state is known. Distinguished from F. avenaceum (CMI Descript. 25) by the sickle-shaped, pedicillate macroconidia; and in culture by the abundant chlamydospores, the ochraceous-brown or cinnamon-Sudan brown sporodochia, and by a higher opt. temp. (25°C.) for growth. In the field, spikelets of cereals infected by F. culmorum produce coral-coloured sporodochia in contrast to those of F. avenaceum which are apricot-coloured (see Bennett, 1928). Fusarium culmorum can cause serious damage to cereals, particularly wheat, both to seedlings and in adult roots, with crop losses amounting to 50-70% in Australia, New Zealand, Canada and the U.S.A. In Sardinia, the disease reached epiphytotic proportions in 1895-96 and again in 1946, and was at first wrongly attributed to Melanospora damnosa, which sometimes follows the attack (10: 20; 26: 482; 27: 85; 28: 300, 643; 41: 426). Serious losses in France resulted in the establishment of a special commission to study the disease in 1929 (8: 636). Dry conditions may favour infection in early stages (9: 586; 17: 306; 26: 482), as well as poor drainage, wet, acid, heavy soils, deep sowing, too heavy applications of organic matter, a high N/K ratio and a high concentration of CO2 (27: 241; 10: 91; 11: 631; 2: 383). Recommendations for control include deep burial of crop residues and long crop rotations (13: 362; 14: 145), late sowing of winter wheat (15: 85), addition of N fertilizers with or without P and K (8: 637; 19: 696; 41: 145) or zinc sulphate (18: 97; 25: 104); and seed treatment with mercurial compounds to reduce-primary infection (7: 710; 14: 688; 27: 136; 35: 371). High soil temperatures, however, which favour the spread of the pathogen, may nullify the beneficial effects of chemical seed treatment (20: 524; 22: 58).
 
Description type:Non-original description 
Description:Fusarium culmorum (W.G. Sm.) Sacc., Sylloge Fungorum 11: 651, 1895.
? Fusisporium culmorum W.G. Sm., Diseases of Field and Garden Crops, London, p. 209, 1884.
Cultures show rapid growth with floccose aerial hyphae; this becomes yellow at the point of the inoculum and the colour spreads throughout the colony; simultaneously on surface of medium a red pigmentation develops which diffuses into the media; this pigment is developed both in the mycelium and in the spores and after 7-10 days, and the colonies assume a deep reddish-brown colouration (pomegranate purple, Ridgway). Microconidia absent. Macroconidia produced occasionally from conidiophores formed laterally on aerial mycelium but more frequently they are formed from loose sporodochia (often these become pionnotal in form with suppression of mycelium), 3-5-septate, slightly curved, strongly dorsiventral, fusoid with apical cell suddenly constricted; 3-septate 26-36 x 4-6 µm, 5-septate 34-40 x 5-6 µm. Chlamydospores oval to globose, generally intercalary but occasionally terminal, smooth to rough-walled, single, in chains, or in clumps.
Hosts: On Gramineae and a wide range of other plant species including the following families: Aizoaceae, Betulaceae, Brassicaceae, Campanulaceae, Caryophyllaceae, Chenopodiaceae, Compositae, Coniferae, Convolvulaceae, Cucurbitaceae, Leguminosae, Liliaceae, Linaceae, Malvaceae, Musaceae, Palmae, Rosaceae, Saxifragaceae, Solanaceae, Violaceae, Vitaceae. Also on fungi (Agaricus and Ustilago spp.) [Wollenweber & Reinking (1935), Gordon (34: 258; 38: 581; 40: 89) and Herb. IMI].
Diseases: Causing cortical rots associated with a pre-emergence blight of seedlings, and a seedling blight, foot and root rot, and head blight of wheat, rye, oats and barley; also cob and stem rot of maize; brown patch of turf; foot rot of asparagus, carnation, leek and pea; and storage rots of apple, potato, sugar-beet and Galtonia bulbs.
Geographical distribution: Africa, North America, Central America & West Indies, South America, Asia, Australasia, and Europe.
Physiological specialization: Several forms have been obtained from wheat showing variation in both morphological characters and pathogenicity (8: 496; 15: 566 22: 58; 28: 447) including isolates from healthy plants (17: 229; 37: 532). Strains from a wide range of unrelated hosts have also been found pathogenic to cereals (8: 373; 17: 250), potato (37: 325), and carnation (9: 37). Saprophytic isolates have been found which were as pathogenic to wheat as those isolated from diseased plants (19: 11; 21: 134; 25: 318).
Transmission: Mainly soil-borne but also in stable manure or compost containing infected straw (13: 23; 14: 735; l9: 649). Fusarium culmorum is a soil inhabitant possessing highly competitive saprophytic ability and unusual tolerance of antibiotic effects [see Garrett (1956, 1963); Rao (1959); 34: 147; 38: 577)]. It may occur in a viable condition in soil to a depth of 50 cm. (19: 11; 13: 23), and remain viable on wheat straw buried in unsterilized soil for 2 years (38: 509). The pathogen over-winters in both mycelial and conidial stages and is highly resistant to cold (17: 305, 306). Secondary infection by air-borne spores produced on lower nodes occurs in wet weather (3: 201; 7: 710; 9: 585), but these are not carried far and have not been recorded in traps (15: 384; 38: 319).
Literature: For general studies on the taxonomy and variability see Wollenweber & Reinking, Die Fusarien, Berlin, 1935, and Snyder & Hansen, Amer. J. Bot. 32(10): 657-666, 1945. Factors influencing parasitism and survival of the pathogen in soil have been reviewed by Garrett, Biology of Root-Infecting Fungi, Cambridge Univ. Press, 1956; see also papers by Rao, Trans. Brit. Mycol. Soc. 42(1): 97-111, 1959; Griffiths & Siddiqi, Trans. Brit. Mycol. Soc. 44(3): 343-353, 1961 (22 refs); Garrett, Trans. Brit. Mycol. Soc. 46(4): 572-576, 1963. For general account of the disease in cereal crops see Bennett, Ann. Appl. Biol. 15(2): 213-244, 1928.
 
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