Oregon Black currant yellows on 'Kantata 50' cultivated in Corvallis, Oregon. The cause of this condition is not known and may be a physiological disorder. Thus far, unlike viral diseases, this condition has not been demonstrated to be transmitted to other plants. The cause of this condition could be a genetic disorder. Symptoms include yellow regions of the leaf or yellow flecks appearing on the edges of the leaf.
Symptoms are more pronounced in the spring, and are overgrown by normal green foliage in the summer.