Dead-arm, sometimes grape canker, is a disease of grapes caused by a deep-seated wood rot of the arms or trunk of the grapevine. As the disease progresses over several years, one or more arms may die, hence the name "deadarm". Eventually the whole vine will die. In the 1970s, dead-arm was identified as really being two diseases, caused by two different fungi, Eutypa lata and Phomopsis viticola (syn. Cryptosporella viticola).
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Although the dead-arm disease is usually looked upon as a malignant disease that often cripples one or more vines, some wine estates have discovered that the arms that are still alive when dead-arm has struck yield a very flavorful wine. One such vineyard belonging to Australian wine producer d'Arenberg have marketed this "Dead Arm" Shiraz, which has received high wine ratings among various wine critics.
Eutypa dieback 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. The fungus also attacks many other hosts such as cherry trees, most other Prunus species, as well as apples, pears and walnuts.
Phomopsis leaf, also called Cane spot or Fruit rot disease, is caused by Phomopsis viticola.