Cooperative Extension: Maine Wild Blueberries

5.10.14 Mummy Berry Infection periods, May 10

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At all of the weather station conditions for a mummy berry fungus infection period occurred from Friday, May 9 or Saturday, May 10.  Please see the table below to see the approximate time when the infection period started in your area.  Most growers in Knox, Lincoln, and Waldo counties have plants that are susceptible and there are mummy berry cups producing spores in these areas.   In Hancock and Washington counties, there are mummy berry cups in the fields producing spores but how far along the blueberry plants have opened vary by field. Growers will need to check their own fields to determine if greater than 40% of flower buds are at F2 and whether they need to spray.

In those areas where there was an infection period, if you have applied fungicide on or after Saturday, May 3 your plants were protected during the infection period this weekend.  If you have not applied fungicides, you have until the evening of Tuesday, May 13, depending upon the rain in your area,  in most areas to apply fungicides (propiconazole or fenbuconazole) to kill any infection.  Other fungicides should be applied as protectants and before infection periods occur.