Mummies are just the beginning of infection. The mummies are only part of what takes place. The fungus overwinters in these infected berries that have fallen to the ground. In the spring, these mummies ‘sprout’ small, mushroom looking structures, with little cups on the end. These are called apothecia, and they produce tons of spores.
The spores spread by wind over fairly long distances. When they land on leaf buds and young shoots, it only takes a few hours or days for ‘primary infection’ to occur, depending on leaf wetness and temperature. Green tissue has to be present for infection. The ideal condition for infection is cool and wet (a common scenario now and early spring). About a week or two after becoming infected, the leaves and shoots wilt and turn brown. This damage can easily be mistaken for frost injury. If flowers are present they can sometimes become blighted, also.
Prevention of mummy berry establishment is key for managing the disease and cleaning the ground. After harvest, and if possible, clean up dropped fruit. Prior to bud break, shallow cultivation, no deeper than one inch, underneath bushes will prevent spore cup development.