Over the years I've had good success with my blue berry plants. However, in the last couple of years the plants form many flowers in the spring and the berries start to develop well then, for some reason they wither up and drop off. Totally no crop, just like a blight of some sort. What can I do to control this problem?
Sounds like it could be a couple of problems. If the berries form and wither just before harvest then if could be mummy berry disease which is very common:
If the flowers wither before forming any fruit then it could be some nasty virus problems that are not quite as common: