Cooperative Extension: Maine Wild Blueberries

5.09.16 Mummy Berry Infection periods, May 6 to May 9

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I had new reports on Friday of pinheads in some fields and dried up cups in other fields near by.  I suspect we are getting near the end, but I think we still have cups in most fields.  With this rainy weather we had over the weekend, many of our fields had one to three infection periods. All fields had an infection period from Saturday through Sunday (May 7 to 8).  Some fields had infection periods over Friday night into Saturday (May 6 to 7)  and some along the coast from Sunday night into Monday (May 8 to 9). Please see the table below for infection events in your area.  Some of our weather stations did not send the weather (due probably weather interference with the cellular signal) for a few time periods so some of the times are estimated from surrounding areas.

If you have applied fungicides within seven to ten days before an infection period, your plants are protected.  Some fungicides, such as propiconazole and fenbuconazole, have kickback activity which can kill off the fungus within about 72 hours after it gets in. Most fungicides recommended for mummy berry have protectant properties and will protect your plants at least seven days after application and depending upon the weather up to ten days.

If you have applied fungicides after April 26 to April 29 (ten to seven days before these current infection periods), your plants were probably protected.  If you have not applied fungicides and wish to, you have up to 72 hours after the infection period start to apply fungicides with kickback activity (fenbuconazole or propiconazole) to protect your plants.   If you are applying a second (or third) application of fungicide, it would be good to rotate to a fungicide with a different mode of action or at least a different chemical to avoid fungicide resistance developing in your field.

Please check your mummy berry plots at the beginning of this week and let me know what is happening since we are coming close to the end of the season.

Contact info: sannis@maine.edu or the Blueberry Hotline 800.897.0757 (in Maine)

Thank you, Seanna Annis