The survey of some factors affecting bark lesion development caused by phytophihora cactorum on common beech and other broadleaved trees

Abstract

The three experiments relating to the pathogenicity of Phytophthora cactorum to beech and other forest tree species were carried out. The experiments were aimed to confirm pathogenicity of the pathogen, to compare its pathogenicity with the other Phytophthora species isolated from woody plants in the Czech Republic (P. gonapodyides, P. cambivora, P. citricola s.l., P. cinnamomi, P. citrophthora), to confirm its substrate specificity and diverse pathogenicity to common forest tree species (common beech, pedunculate oak, sycamore, small-leaved lime, black alder, common ash) and to determine the influence of excessive watering on the stem canker development. We found out that the tested isolate of P. cactorum was more effective to the host than isolates of P. gonapodyides and P. cambivora. The isolates of P. cinnamomi and P. citrophthora caused the largest necroses. It emerged that all tested tree species were susceptible to P. cactorum. The most susceptible tree species were sycamore and common beech. The most resistant tree species were common ash and pedunculate oak. The existence of substrate specificity of the pathogen was unequivocally confirmed. It was found out that the water stress could play an important role in the bark lesion development. We found out important differences in lesion development in different periods during growing season (June, September).