Probable Mummy berry infection in most locations, May 1 2020
As you may have guessed, weather conditions were suitable for mummy berry infection periods at most weather station locations from the early morning (4am to 8am) on Friday May 1st through to Friday night. I expect plants were ready and mummy berry cups were present in the Midcoast region and in many fields Downeast. The weather station site in Crawford was the only one that we looked at early in the week that may not have had plants far enough along yet.
If you applied fungicide within seven days before this infection period, your plants were likely protected. If you have not applied fungicide, you have until approximately the evening of May 3rd to apply propiconazole or fenbuconazole which have some activity in killing early infections. Other fungicides have only been checked for protectant activities and need to be applied before infection periods occur.
Please check with your processor before applying fungicides and follow the fungicide recommendations for 2020. You can find the “Disease Management Chart 2020” on this website https://extension.umaine.edu/blueberries/factsheets/disease-2/
Please let me know how your mummy berry plots are doing and if your plants are still getting close to F2, I would like to know that too.