The most common Phytophthora species on beech in Serbia: morphological and colony growth patterns

Abstract

The paper presents the results of the studies of the main morphological and colony growth and shape patterns of isolated Phytophthora species in beech stands in Serbia. After the recorded symptoms in different beech stands in Serbia, sampling and isolation of Phytophthora species was performed. The next step was determination of colony growth characteristics of obtained isolates and their grouping according to known patterns and keys. The most numerous were the isolates with semi-aerial, petaloid mycelium and with chrysanthemоus shape, relatively fast growing. This species is homothallic and form globose oogonia and oospores and antheridia with different shapes. Sporangia are semipapillate with very variable shapes and this species was identified as Phytophthora plurivora. Group of isolates with aerial, velvety and with no special shape of colony, heterothallic and with nonpapillate sporangia were identified as P. cambivora. Two groups of isolates were very similar in cultures, as well as in nonpapillate sporangia shape. Both are sterile with medium growth rate colonies, however the first species did not formed the chlamydospores and hyphal swellings in chains and it was identified as P. gonapodyides, while the second species has produced chlamydospores and hyphal swellings in chains and was identified as Phytophthora taxon ’Pg chlamydo’. Isolated species are posing great risks to forestry and biodiversity and future studies on occurence and the role of these pathogens in beech trees decline are required.