The effect of pruning time on the incidence of Eutypa armeniacae infection in apricot trees

Abstract

In a field experiment during 1964-66, we compared large and small pruning wounds on apricot for infection by Eutypa armeniacae following three different times of pruning. April pruning resulted in significantly more wounds, both large and small, becoming infected than did June or August pruning. The difference between the infection levels following June and August pruning was significant for large wounds but not for small wounds. At each pruning time, significantly more large than small wounds became infected. Air sampling close to an ascospore source in five consecutive years has confirmed the existence of a regular seasonal cycle of ascospore output from stromata of E. armeniacae under South Australian conditions.