Bark Reaction of Different Oak Species to Cryphonectria parasitica

摘要

Our main goal was to study the susceptibility of oak species to the plant pathogenic fungus Cryphonectria parasitica. Virulence of different isolates was examined on dormant sticks of 9 different oak species (Quercus spp.) and on European chestnut (Castanea sativa) as a control. Branches were infected with virulent isolates. The experiments were done in 4 repetitions. The treated branches were inoculated for 36 days, and then the size of caused cankers were measured. The necroses were ellipse shaped mostly. Shorter and longer diagonals of the ellipses were measured, and the size of the damaged bark surface was determined by using the ellipse calculation formula [(axb)xπ]. According to the results achieved red oak (Quercus rubra) was extremely susceptible to the fungus. Necrosis on the red oak caused by C. parasitica were significantly bigger in size than those were on the chestnut branches. Q. rubra and C. sativa were more susceptible than other tree species, and sessile oak (Q. petraea) and the pedunculate oak (Q. robur) also showed a great susceptibility. Nesroses were the smallest on Q. robur f.fastigiata.