Q: I have a long row of mature blueberry plants. For the past two years, all of my berries have turned brown and dropped just prior to maturing. I theorized this was mummy berry disease so I replaced all the mulch this past winter, to no avail this summer!
A: The symptoms sure sound like mummy berry. Once the disease infects a flower cluster in spring, the fungus becomes slightly fragrant and secretes sugars, making it attractive to insects. The insects spread the disease further through the plant. The fruit looks fine until it begins ripening, at which point it falls off. You made a good start by replacing the mulch but that will have to be done yearly. Before the leaves fall, cultivate shallowly around plants to bury mummified fruit. Consider spraying the plants with a garden fungicide from budbreak to the end of flowering.