Identify the problem. New growth and flower blossoms that blacken and die have a fungus called "mummy berry." This fungus causes hard, dry berries. "Godriona canker" causes small red spots on foliage near the ground, and causes the plant to wilt and die back.
Remove infected berries immediately. Prune off any infected foliage.
Put urea prills around the base of the plants in spring to kill fungus spores. Always follow manufacturer directions for urea prills.
Prune your blueberry bushes according to standard pruning practices to remove the possibility of disease in the future.
Prevent future disease by fertilizing blueberry bushes in spring rather than fall.
Watch your plants for nutritional deficiencies as well. If blueberry plants have yellow leaves, it means that they have an iron deficiency.
Fertilize your plants with an iron-heavy supplement to get them back in shape.