5.25.20 Mummy berry season over in most areas for 2020 – symptoms to look for

This dry, warm weather will have finished off Monilinia cups for this year in most blueberry growing areas.  If you do still see cups in your area, please let me know!  You may have seen mummy berry symptoms of dead leaves and flowers with the base of the tissue having a grey powdery spore production (see pictures below)

There has been cold weather over the past couple of weeks that may have affected blueberry development (see pictures below).  You may see some frost damage on leaves and possibly flowers.   The weather for the next week is forecast to be warm with little chance of frost.

It is a good time to look for  Botrytis symptoms in your field.  You will see dead flower blossoms with long black hairs and possibly grey powdery spores at the end of the hairs (see pictures below).  Botrytis needs long periods of wetness to cause infection, but the fungus does grow faster and cause quicker infections in warm, wet conditions.  The rain forecast for the end of the week may cause Botrytis infections IF you have plants with almost open or open flowers AND you already have Botrytis infections in the field.

Picture of frost damage of blossoms, all flowers on a stem tend to be affected. On leaves, the youngest leaf in the center of the cluster have been killed.

Mummyberry Blight
Wild blueberry flowers and leaves with symptoms of mummy berry blight, Yellow circles are around grey spore masses that are carried by insects to healthy flowers
Botrytis blossom blight symptoms on flowers. Notice hairs sticking out of flowers.
Botrytis infected flowers showing black “hairs” with spores