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Remarks (public):For a complete description including images see www.cababstractsplus.org/dfb 
Remarks (internal):Control in Camellia sinensis is by digging up and burning infected plants and removing any infected trees of other genera in the area (Petch, 1923). It may be eradicated from small areas by soil fumigation (49, 2170b) and ring-barking of shade trees has also been recommended (49, 245). The removal of diseased tissue and disinfection with organomercurial compounds followed by the application of prowax has also been effective (41: 479). There is a risk of infection from buried diseased tissues (17: 314). In Europe the conidialstate forms in the spring and the perithecial stroma forms through the summer and ripens in the autumn. Wilkins (1938, 1939) provides data on the optimal conditions for the germination of ascospores and conidia. Ustulina zonata has been considered to differ from U. deusta by some authors in having slightly wider ascospores, predominating in the tropics, and its parasitism on Hevea, etc. (Petch, 1928; Miller, 1961) but does not seem to be specifically distinct although it may merit recognition as an infraspecific taxon. Ustulina deusta is a readily identifiable species which is distinguished from species of Hypoxylon by its large perithecia and ascospores and the way in which the massive carbonaceous stroma is easily removed from the host tissues. The stromata also characteristically occur on the basal parts of infected trees and shrubs while those of species of Hypoxylon may often be found higher up the plant as well.
 
Description type:Non-original description 
Description:Ustulina deusta (Hoffm.: Fr.) Lind, Danish fungi: 252, 1913.
= Sphaeria deusta Hoffm.: Fr., Systema mycologicum 2: 345, 1823.
= Sphaeria deusta Hoffm., Vegetabilia cryptogama 1: 3, 1787.
= Nemania deusta (Hoffm.: Fr.) Gray, 1821.
= Hypoxylon deustum (Hoffm.: Fr.) Grev., 1828.
= Ustulina vulgaris Tul., 1863.
= Hypoxylon ustulatum (Bull.) Kickx, 1835.
= Ustulina zonata (Lév.) Sacc., 1882.
= Ustulina maxima Web. ex Wettst., 1885.
For further synonyms see Miller (1961, pp. 84-85).
Stromata massive, orbicular to effuse, forming discrete cushions erumpent through the periderm or confluent, undulate to pulvinate, arising on the site of the conidial state, greyish-white and leathery at first, becoming reddish-black then black and brittle with age, readily detached from the substratum (separating along the line of the perithecial bases), stromatic tissue internally whitish, composed of vertical fibrous masses which disintegrate in old stroma, crust usually 1-3,5 mm thick, but when perennial becoming thicker and concentrically zoned. Perithecia scattered in the stroma, immersed in its whitish flesh, with short projecting black papillate ostioles, very large, vertically orientated and elongated, to 1,5 x 1 mm. Asci cylindrical, very thin-walled, often becoming gelatinized, 8-spored,190-300 x 8-15 µm, stalk 50-60 µm long. Paraphyses numerous, branching from the base, filiform. Ascospores uniseriate, dark brown to black, narrowly ellipsoid to fusiform, sides inequilateral, apices acute, with a longitudinal furrow which is sometimes indistinct, 26-40 x 6-13 µm. Conidial state on host precedes the formation of the perfect state stromata, greyish-white to greyish-brown, forming an effuse continuous layer where the periderm has disappeared, consisting of vertically orientated compacted tufts of parallel conidiophores, usually c. 0,5 mm thick. Cultures growing readily on PDA and MA at 23°C, white to grey at first but becoming greyish-brown with the formation of conidia on vertical tufts of conidiophores, becoming black in reverse after 2-3 weeks. Conidiophores hyaline to pale fuscous, sparsely branched. Conidia hyaline to pale fuscous, simple, narrowly ovate,smooth-walled, 5-7 (-9) x 2-3,5 µm.
Hosts: On stumps, butts and dead roots of many genera of trees and shrubs. Particularly common on Fagus sylvatica in Europe. Host genera of economic importance include Camellia, Citrus, Cocos, Coffea, Elaeis, Hevea, Nicotiana and Theabroma. Wilkins (1934) provides a host index.
Diseases: Cause of 'charcoal base rot' of Elaeis and Hevea; 'charcoal stump rot' and root disease of Camellia; 'collar rot' of Hevea; butt rott of Fagus; 'white rot' of Tilia; etc. In Elaeis the base is affected by a hard dry rot resulting in the progressive death of the fronds leading to death (Turner, 1971). Attacks the cell walls of tracheids so that infected wood is permeated with conspicuous black lines. Reported as responsible for the death of young Tectona grandis in Tanzania (42: 224). Usually now regarded as of little economic importance but often serious locally. The pathogenic tendencies are less pronounced in temperate than subtropical and tropical regions.
Geographical distribution: Cosmopolitan (CMI Map 417, ed. 1, 1966). In every country fide Miller (1961).
Physiological specialization: None known (but see under 'Notes').
Transmission: In temperate regions wind-borne conidia are probably the most important cause of infection (Wilkins, 1938, 1939) and enter through wounds, including areas which have been scorched, and pruned branches (41: 479). Infection may also arise from ascospores and through the contact of lateral roots (Petch, 1928), and nearby infected trees and shrubs of other genera (Petch, 1923).
Literature: Wilkins, Trans. Br. mycol. Soc. 18: 320-346, 1934 (bibliography, host-index); Wilkins, Trans. Br. mycol. Soc. 22: 47-93, 1938; Wilkins, Trans. Br. mycol. Soc. 23: 65-85, 1939 (infection); Moore, British Parasitic Fungi, 1959 (host index for Britain); Petch, Trans. Br. mycol. Soc. 13: 238-253, 1928 (taxonomy); Miller, A Monograph of the World Species of Hypoxylon, 1961 (taxonomy); Petch, The Diseases and Pests of the Rubber Tree, 1921 (on Hevea); Petch, The Diseases of the Tea Bush, 1923 (on Camellia): Turner, Phytopath. Pap. 14, 1971 (on Elaeis) Wilkins, Trans. Br. mycol. Soc. 20: 133-156, 1936 (on Tilia).

 
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