Early symptoms of Phomopsis twig blight. Blueberry twig killed by Phomopsis . Individual buds turn brown and die, followed by browning and necrosis of bark around the bud as the fungus spreads from the blighted bud into the twig. The disease usually spreads down the twig until most or all of the fruit buds on an individual twig are killed. Twig blight can continue to infect fruit-bearing twigs at all stages of development.
New infections occur continually as buds open, flower, and produce fruit.
After the twig is killed, fruiting bodies called pycnidia are produced just under the surface of the bark. During routine winter pruning, careful hand-pruning can be performed to remove infected twigs prior to spore release in the spring. This will decrease the amount of disease inoculum present at budbreak. While this technique may not be practical for large commercial operations, growers with less acreage and home gardeners should benefit from this sanitation method. The highbush cultivars Murphy and Harrison are highly susceptible to this disease and should not be grown without using a fungicidal spray program.