The picture below from the University of Maine shows what susceptible floral buds look like.
Once Buds reach the F2 stage, a wetness period needs to be of sufficient duration in order to be an infection period. See the table below developed by Dr. Paul Hildebrand and Rick Delbridge to help determine if there is an infection period.
Treatments should not be considered until greater than 40% of the fruit buds are past the F2 stage.
Update from reporting sites:
There is one field in South West Nova Scotia that is beyond the 40% F2 stage, other fields in that region are beginning to approach that threshold.
I have no reported fields in Central Nova Scotia that are at or near the 40% F2 stage. However, with the forecast of warm weather for the next several days, growers should begin monitoring their fields to determine the level of bud development.
Look for the next update late in the afternoon on Friday, April 28th.