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Remarks (public):For a complete description including images see www.cababstractsplus.org/dfb 
Remarks (internal):This species causing beech bark disease was referred to Nectria ditiasima by Hartig (see Booth, 1959) and in an extensive study of its occurrence in Denmark by Thomsen, Buckwald and Hauberg, they referred it to Nectria galligena.
Evidence suggests that infection and spread occur chiefly during the dormant period of the host and growth of the fungus was found to occur at 5°C (51, 4168), although no seasonal variation was found in the ability of N. coccinea to infect beech, nor in the size of the cankers produced (55, 3751b). Control may be possible by the selection of resistant varieties. Where practicable the scale insects can be controlled by using tar-oil winter wash.
 
Description type:Non-original description 
Description:Nectria coccinea (Pers.: Fr.) Fr., Summa Veg. Scand. II: 388, 1849.
Sphaeria coccinea Pers., Icon. & Descript. Fung. II: 47, 1800.
Sphaeria coccinea Pers.: Fr., Syst. Mycol. II: 412, 1823.
Cucurbitaria coccinea (Pers.: Fr.) Gray, 1821.
Creonectria coccinea (Pers.: Fr.) Seaver, 1909.
Perithecia typically forming in groups of 5-35 on a common stroma which forms in the cortical tissue of the host, when developing on exposed wood often solitary, scattered and without a stroma,.250-350 µm diam., oval to sub-globose with a pointed often darker ostiole papilla, appearing translucent when freshly developed but become rougher and darker with age. Asci 75-100 x 7-10 µm, cylindrical with a rounded apex and with 8 monostichous to subdistichous ascospores, Ascospores hyaline, 1-septate, becoming light brown and slightly verrucose, 12-15 x 5-6 µm. Conidial state belonging to the form-genus Cylindrocarpon. Cultures produce a floccose to fibrous yellowish-white to greyish-brown mycelium. Microconidia forming after 2-3 days, initially from lateral phialides but later from well developed conidiophores, 4-9 x 1,5-3 µm, cylindrical with rounded ends, occasionally slightly curved and may develop a central septum. Macroconidia developing later from somewhat larger phialides than those producing the microconidia, hyaline, cylindrical and narrowing slightly towards the apex and base, when mature with 3-7 septa, 46-80 x 6-7 µm. Chlamydospores forming sparsely in older cultures often from the cells of the macroconidia.
Hosts: Fagus sylvatica (beech)
Disease: Beech bark disease, in association with beech scale (Cryptococcus fagi); this is the most serious disease of beech in Britain. It has also been reported as pathogenic to Ganothus velutinus (49, 1677). The perithecia are also frequently found on many other hard wood and coniferous trees.
Geographical distribution: In association with beech bark disease it is only known in Europe (Denmark, France, UK) and eastern North America. It is common in northern Europe on other hosts probably as a saprophyte and it has also been recorded in Australia, Hong Kong, India and New Gledonia.
Physiologic specialization: No doubt Physiologic specialization occurs as in Nectria galligena (Flack & Swinburne, 1977). There is no information available relating to host specificity but the species is common in beech woodland where beech bark disease has not been observed. Resistance of beech trees to N. coccinea and Cryptococcus fagi by callus formation isolating the infected area has been detected (54, 4173) and a method of checking for resistance has been suggested (54, 4171) by observing callus formation in young plants.
Transmission: Ascospore discharge is associated with wet conditions (54, 5092). The ascospores are disseminated in air and penetration of the host is through bark fissures or bark wounds caused by scale insects (54, 5560).
Literature: Thomsen, Buckwald & Hauberg, Angreb af Cryptococcusfagi, Nectria galligena og andre parasiter pea Bog i Danmark 1939-43, Forstlige Forsogsvaesen Danmark 18: 97-326, 1949; Booth, Studies of Pyrenomycetes IV. Nectria (Part 1). Mycological Paper 73: 1959; Parker, Beech Bark Disease, Forestry Commission Forest Record 96: 1-15, 1974. Flack & Swinburne, Host range of Nectria galligena Bres. and the pathogenicity of some Northern Ireland isolates, Transactions of the British Mycological Society 68: 185-192, 1977.

 
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