Mummy Berry Forecast for Monday April 20th to Tuesday April 21st
For Knox, Lincoln and lower Waldo county.
Mummy berry cups producing spores were found in South Hope on Wednesday April 15th. The blueberry plants were not susceptible at that time since less than 40% of stems had flower buds at the crown stage.

There is a chance of an infection period occurring around the Union area with the rain forecasted to start Tuesday night. Whether infection does occur will depend upon the actual temperature during and length of time of rain or rain and fog in your field.

Whether you need to spray fungicides for mummy berry control will also depend upon how far along your plants are. IF more than 40% of random stems (4 out of 10) in your field have buds at the crown stage (see photo) your plants are now susceptible to the fungus.

If the weather forecast suggests rain or rain and fog for longer than 10 hours you should check the forecast for the temperature during that period. AT about 36 F, 24 hours of leaf wetness is required for infection. At 43 F, only 10 hours of leaf wetness is required to cause infection.

Please check Factsheet #217 at the Wild Blueberry extension site (http://wildblueberries.maine.edu) for more information on the chance of infection depending upon temperature and length of leaf wetness. Please see Factsheet #219 for recommended disease control methods.