|
Botryosphaeria dothidea (Moug. : Fr.) Ces. & De Not., Comm. Soc. Crit. It. 1: 215. 1863.
º
Sphaeria dothidea Moug. : Fr., Syst. Mycol. 2: 423. 1823.
|
|||||||||||
|
Characteristics on the host —Ascomata initially immersed, either separate or grouped in complex multilocular stromata, becoming erumpent through the epidermis and opening through a well-developed ostiole, individual locules 180–250 µm in diameter, wall composed of dark, thick-walled textura angularis, becoming paler and thinner walled towards the interior, contents conspicuously white when dry, opening through a periphysate ostiole. Asci bitunicate, clavate, stipitate 84–176 × 16–24 µm. Ascospores ellipsoid to broadly fusoid, widest in the middle or upper third, hyaline, smooth, thin-walled, unicellular, tapering to the obtuse base and apex, multiguttulate, eight spores in each ascus, irregularly biseriate (15–)18.0–25.5(–28) × (6–)7.5–12.0(–14) µm. Pseudoparaphyses hyaline, septate, branched, 2–3.5 µm wide. Conidiomata often develop on the same stroma as the ascomata, mostly individual but occasionally aggregated and confluent in a single stroma, externally black, the wall composed of thick-walled textura angularis becoming progressively paler and thinner walled towards the inner layers. Conidiophores hyaline, cylindrical, smooth, branched at the base, 0–1 septate, 14–24 × 2–3 µm, entire locule lined with conidiophores. Conidiogenous cells initially holoblastic, becoming enteroblastic, integrated, hyaline, smooth, 6–20 × 2–5 µm, cylindrical producing one or more conidia apically, often proliferating percurrently to produce conidia at successively higher levels on annellate conidiogenous cells, or proliferating at the same level resulting in periclinal thickenings. Conidia hyaline, thin-walled, smooth, fusiform to fusiform-elliptical, straight, apex subobtuse, base truncate bearing a minute marginal frill, (18–)21–28.5(–30) × (3.5–)4–4.5(–6) µm, mean and standard deviation of 50 conidia = 23.5 ± 2.1 × 5.8 ± 0.5 µm and length/width ratio of 4.1.
Characteristics in culture — Cultures initially white with abundant aerial mycelium, gradually becoming grey to dark grey. The reverse side of the colonies at first white, but after 2–3 days becoming dark green to olive green from the centre. This colouration gradually spreads to the edge and becomes darker from the centre until the entire underside of the colony is black. Conidiomata multilocular and eustromatic opening through several non-papillate pores, and oozing spores after 8 d at 25 C on OA, with up to 500 conidiomata per plate. Conidia fusiform to fusiform elliptical with a subobtuse apex and a truncate base bearing a minute basal frill, (18–)21–28.5(–30) × (3.5–)4–4.5(–6) µm, mean and standard deviation of 50 conidia = 24.7 ± 1.9 × 4.4 ± 0.4 µm. Length/width ratios in the range of 3.8–6.3 with an average of 5.3 ± 0.6. Conidia not becoming septate or darker with age. Microconidia rarely seen. Notes: — When Cesati & De Notaris (1863) described the genus Botryosphaeria Ces. & De Not. they did not designate a type species. Von Höhnel (1909) suggested B. berengeriana De Not. as lectotype, while Theissen & Sydow (1915) suggested B. quercuum (Schwein.) Sacc. Both proposals were rejected because these species were not included in the original description by Cesati & De Notaris (1863). Barr (1972) proposed B. dothidea (Moug. : Fr.) Ces. & De Not. since it was one of the original species described and it conforms with Saccardo's (1877) emendation. This proposal has generally been accepted. Recently, Slippers et al (2004) resolved many of the taxonomic problems associated with B. dothidea and proposed an epitype to stabilize the name. They also provide a modern description based on the neotype and epitype.
References Arx JA von & Müller E. 1954. Die Gattungen der amerosporen Pyrenomyceten. Beitrage zur Kryptogamenflora der Schweiz 11(1): 1–434. Denman S, Crous PW, Taylor JW, Kang J-C, Pascoe I & Wingfield MJ. 2000. An overview of the taxonomic history of Botryosphaeria, and a re-evluation of its anamorphs based on morphology and ITS rDNA phylogeny. In: Molecules, morphology and classification: Towards monophyletic genera in the Ascomycetes. Studies in Mycology 45: 129–140. Grossenbacher JG & Duggar BM. 1911. A contribution to the life-history, parasitism and biology of Botryosphaeria ribis. New York Agricultural Experimental Station Technical Bulletin 18: 115–190. Maas JL & Uecker FA. 1984. Botryosphaeria dothidea canker of thornless blackberry. Plant Disease 68: 720–726. Michailides TJ. 1991. Pathogenicity, distribution, sources of inoculum, and infection courts of Botryosphaeria dothidea on pistachio. Phytopathology 81: 566–573. Punithalingam E & Holliday P. 1973. Botryosphaeria ribis. CMI desccriptions of Pathogenic Fungi and Bacteria No. 395. Commonwealth Agricultural Bureaux, Kew, UK. Ramos LJ, Lara SP, McMillan RT Jr & Narayan KR. 1991. Tip dieback of mango (Mangifera indica) caused by Botryosphaeria ribis. Plant Disease 75: 315–318. Rumbos IC. 1987. Twig dieback of walnut trees induced by Botryosphaeria ribis. Plant Pathology 36: 602–605. Slippers B, Crous PW, Denman S, Coutinho TA, Wingfield BD & Wingfield MJ. 2004. Combined multiple gene genealogies and phenotypic characters differentiate several species previously identified as Botryosphaeria dothidea. Mycologia 96: 83–101. Witcher W & Clayton CN. 1963. Blueberry stem blight caused by Botryosphaeria dothidea (B. ribis). Phytopathology 53: 705–712. Botryosphaeria dothidea. Version 02.2 saved 8 October
2007 |
