Newly recognized Dying Arm Disease of grapevines

Abstract

A dying arm disease of grapevine is important on some grape varieties in California. Leaf and shoot symptoms are readily apparent in mid-April, when healthy shoots are 6 to 12 inches long. Initially, single arms are affected, with the infection spreading to the main framework of the vine in succeeding years. Yield declines accordingly. The fungus causing apricot dieback (Eutypa armeniacae [impf. Cytosporina]) has been consistently isolated from diseased grapevine tissues.