Twig Blight is another canker disease, caused by Phomopsis vaccinii . This is currently the most prevalent twig canker of blueberries in New England. This disease is most severe in seasons following winters with mild spells interspersed with cold weather. Periods of hot, dry weather during the growing season may predispose plants to this disease. Symptoms first appear on small twigs and then spread to larger branches.
Leaves turn reddish and remain attached to the stem.
They can be at ground level up to several feet above the ground. Side branches that become encompassed by the canker will wilt in hot weather. The cankers become covered with tiny black dots, which are the fungal spore producing structures. The cankers are similar to the Fusicoccum cankers, but do not have the target-like appearance. The spores enter the plant through wounds, including wounds from frost or winter injury, so it is important to avoid wounding the plants.