NEOFUSICOCCUM PARVUM, BLUEBERRY PATHOGEN IN ARGENTINA

E.R. Wright, A. Mandolesi , M.C. Rivera, B.A. Pérez
Buenos Aires province constitutes one of the main blueberry (Vaccinium corymbossum) production areas in Argentina. During disease surveys in 2008-2009, a new pathology was observed for this region. In Chascomús, twig and stem blight developed on three-year old plants of V. corymbossum ‘Brighitta’ and ‘Duke’. Disease incidence reached 40%. Plants could occasionally die. Diseased samples were surface disinfected with 0.2% NaOCl and cultivated on 2% Potato Dextrose Agar (PDA) at 20°C. After 21 days under a 12-hour photoperiod, the initially white fungal colonies showed abundant gray to dark gray aerial mycelium, with no sporulation. Pycnidia only developed when the fungus was cultivated on sterilized pine needles placed on 2% water agar (WA), at 22°C. Conidia were fusiform to elliptic, with a subobtuse apex and truncate base, hyaline, non-septate. Afterwards conidia frequently became olivaceous and developed 1-2 septa with a darker middle cell. Mean conidial dimensions were 14.68×5.85 μm. The teleomorph was not observed. To proof pathogenicity, one cm2 PDA plugs with fungal development were placed on the stem base of previously injured one-year-old blueberry plants of cultivar ‘Brighitta’. Initial characteristic symptoms were observed after a week. At day 15, some twigs showed blight up to 6 to 10 cm. After a month, blight reached 20 to 30 cm long. Uninoculated plants remained symptomless. The pathogen was identified as Neofusicoccum parvum. To our knowledge, this paper constitutes the first reference of N. parvum in Buenos Aires, Argentina, as pathogen on blueberry plants.
Wright, E.R., Mandolesi , A., Rivera, M.C. and Pérez , B.A. (2012). NEOFUSICOCCUM PARVUM, BLUEBERRY PATHOGEN IN ARGENTINA. Acta Hortic. 926, 619-623
DOI: 10.17660/ActaHortic.2012.926.89
https://doi.org/10.17660/ActaHortic.2012.926.89
blight, Vaccinium corymbossum, diagnosis, Buenos Aires, fungus
English

Acta Horticulturae