APS Abstract of Presentation

Identification of species of Botryosphaeria, Pestalotiopsis and Phomopsis in blueberry in Chile
J. G. Espinoza (1), E. X. Briceno (1), B. A. LATORRE (1)
(1) Facultad de Agronomia, Pontificia Universidad Catolica de Chile, Santiago, Chile
Phytopathology 98:S51

Blueberry (Vaccinium spp.) production has increased considerable in Chile, today with over 8,500 ha, across a range of diverse soil conditions and climate zones. The objective of this study was to identify the species of wood pathogens associated to stem canker and dieback commonly observed in blueberry in Chile. Symptoms consisted on reddish to dark brown necrotic lesions on twigs and stems, cankered tissues below the bark, dark brown vascular discoloration and foliar necrosis and dieback. Eventually disease plants died. Disease incidence varied from 15 to 45%. A total of 22 plantings were surveyed between 2005 and 2007. On the basis of colony characteristics, conidia morphology and molecular analysis of the ITS region of the genomic DNA, and/or beta-tubulin gene and elongation-factor-1alpha, the following fungi were identified Botryosphaeria australis, B. dothidea, B. parva, B. ribis, Neofusicoccum corticosae, N. mediterraneum, Pestalotiopsis clavispora, P. neglecta, Truncatella angustata, Phomopsis viticola and Ph. australafricana. These species were found alone or they were co-isolated from samples taken in the same blueberry planting. Out of 82 samples, species of Pestalotiopsis were the most frequently isolated fungi (60%) followed by species of Phomopsis (24%) and Botryosphaeria (16%). With the exception of Ph. viticola all other species were pathogenic in detached blueberry stems and in 2-yr-old blueberry plants cvs. cv. O’Neal. These pathogens were consistently isolated from inoculated plants, confirming Koch’s postulates. Therefore, these results demonstrate that the stem canker and dieback of blueberry in Chile can be due to species of the genus Botryosphaeria, Pestalotiospsis and Phomopsis.