Cryphonectria parasitica is extremely virulent in the chestnut trees and chestnut coppiced stands. it infects above ground parts of trees and kilis them. Conidia are produced and dispersed throughout the year, perithecia eject ascospores from early spring through Iate fall, Ascospores can infect oak, beech and sumac when the population of chestnut sprouts becomes too sparse, but theyare not "super pathogens" on the other species. Among the studies began in Europe and under investigation around the world, hypovirulence process seems very promising for figthing with C. parasitica which is very dangerous fungus and threatens chestnut forest.