Morphological Diversity of Phomopsis vaccinii Isolates from Cranberry (Vaccinium macrocarpon Ait.) in Latvia

Abstract

Abstract Phomopsis vaccinii cause a serious disease of blueberry, cranberry and other Vaccinium crops in the North America and Europe as well. Over 1000 species names are described by Phomopsis spp., but their biology and life style are mostly unknown. Identification of P. vaccinii by methods of classical phytopathology is difficult and complicate, because many species are morphologically similar to P. vaccinii, and P. vaccinii itself has diverse patterns of colony morphology. For this investigation P. vaccinii isolates were obtained from five cranberry plantations in different locations of Latvia (Babite, Alsunga, Rucava, Ape and Pargauja municipality) from berries affected by viscid rot at harvest and storage in 2010. Altogether 44 P. vaccinii isolates were cultivated on potato dextrose agar for description of colony morphology. In order to find some relationships between samples, the isolates were arranged in different groups on the basis of mycelium color and structure (zoning), reverse pigmentation, pycnidium formation time, size, location, number and size of conidia. During this study the colonies of P. vaccinii from cranberry in Latvia showed different morphological features in culture and no relationships between growing regions and groups of isolates were found. P. vaccinii is easy to confuse with other Phomopsis species if only classical phytopathological methods are used.