Eutypa dieback, also known as dead arm, is caused by Eutypa lata (synonym: Eutypa armeniacae) which infects fresh pruning wounds when there is adequate moisture on the vine, such as just after a rain.
Dead arm disease, which is caused by Eutypa lata (synonym: Eutypa armeniacae), develops in fresh pruning cuts of vines whenever there is adequate water availability, particularly following rainfall.