Evaluation of superficial canker instability for hypovirulent Cryphonectria parasitica inoculated on American chestnut trees

Abstract

SummaryHypovirulent strains of Cryphonectria parasitica produced superficial cankers on American chestnut (Castanea dentata) that were unstable for superficiality after one winter. Some unstable cankers yielded C. parasitica isolates that had high virulence on American chestnut trees and were vegetatively incompatible with the original inoculated hypovirulent strain, whereas other unstable cankers yielded isolates that had low virulence and were vegetatively compatible with the original hypovirulent strain.