Development is still variable across the province but we are moving into full bloom in many areas.
Long, warm, wet periods are ideal for Botrytis infection. Dense canopies that stay wet or have continual wet periods (daily fog) are very prone to this disease. Over the last week or so we have had several frost or near frost events across the province. If tissue is damaged by frost or another disease, like Monilinia, this can encourage Botrytis infection.
If you have a history of Botrytis infections, a control should be considered in early bloom (10-20% open flower) to protect the open flower and bloom that is not quite open but in the late pink bud stage.
Also but putting a control on at this time, the canopy is not fully closed and it is easier to get more of the product deeper into the canopy and protect more of the bloom further down the stem.
As always check with your buyer to see what products are allowable for their markets, and review the pest management guide to see what products are registered.
http://www.perennia.ca/wp-content/uploads/2015/08/Wild-Blueberry-Pest-Guide-2018.pdf
http://www.perennia.ca/wp-content/uploads/2015/08/Wild-Blueberry-Fungicide-Chart-2018.pdf