Wild Blueberry Newsletter April 2021

Wild Blueberry Newsletter header graphic, text and a photo of blueberries and leaves

April 2021

Dear Growers, Processors and Stakeholders,

It’s an early spring! Based on our phenology and weather data collected in Maine and the National Phenology Network, our bloom will likely be earlier than normal, therefore the risk of having another late frost event during bloom is high.

Check out Maine wild blueberry plant development on our Phenology Tracker, which is updated weekly. Here is our first week of data. Please walk your field to determine the majority stage of development before spraying for mummy berry. Keep in mind that only 36 stems were checked at each location to create this table (6 stems from 6 plants) and they were checked last week.

Table/first wk of data

Mummy Berry Alert

Bud swell is well underway in Waldo, Knox, Lincoln, Hancock, and Washington counties. On Monday, April 12, mummy berry pinheads were seen in Orono plots, which have heavy wet soil. On Thursday, April 15, pinheads were found in one plot at BBHF in Jonesboro. The wet weather is going to produce apothecia in the week of April 19.
Please check your mummy berry plots and plants and let Dr. Seanna Annis know how they are doing (sannis@maine.edu or call 207.581.2621).

App and Website for Weather Stations and Disease Forecast

Mummy berry forecasting season is approaching fast. There is a website and smart phone app available to provide up-to-date disease forecast data and information collected by the blueberry weather stations. It is available as a website: https://app.agrinet.us/ and as an App for a smartphone (Android or iOS).  Please search for “AgriNET” made by Tuctronics in your app store.


Season updates and more information about the app will be available on the UMaine Wild Blueberry Website under Publications > Disease Blog (see link on map in app). Seanna Annis will still send disease reports as needed via email list, Disease Blog, and on the Blueberry hotline (800.897.0757) under disease option 3. If you wish to be added to the email list, please send her an email at sannis@maine.edu.

Maine Drought Outlook for 2021 Season

According to the Agriculture Water Management Board Meeting in March 2021, Rob Marvinney, the State Geologist reported the following:

  • Current river flow conditions are below normal
  • Groundwater levels are normal to below normal
  • Snow pack is normal to below normal for this time of year
  • Three-month precipitation outlook is encouraging
  • Therefore there is concern for continuing drought in 2021

Weather Report from Winter and Spring 2021


The Maine statewide winter (December 2020-February 2021) average temperature was 22.4°F, ranking the third warmest since 1895. This was 1.2°F warmer than the average temperature of the 2019-2020 winter and 6.8°F warmer than the 1901-2000 historical mean. Total precipitation was 10 inches, making this the 48th wettest winter since 1895. This was 1.9 inches less than the total for 2020 and 0.4 inch above the 1901-2000 historical mean.


Maine statewide spring data is recorded for the time period between March-May each year. Data collected so far for March 2021 is as follows. Average temperature was 29.5°F. This was 0.1°F cooler than the average temperature of 2019 and 3.6°F warmer than the 1901-2000 historical mean. Total precipitation was 1.89 inches. This was 0.84 inch less than the total for March 2020 and 1.43 inches less than the 1901-2000 historical mean.

Tick Season

Deer ticks and other tick species that carry human diseases are on the rise in Maine and have been seen in Maine wild blueberry fields. Be sure to add a “tick check” to your daily routine and check out UMaine Extension’s tick services and prevention tips.

 Field Day Updates

The UMaine Blueberry Hill Farm field day will be held in-person in smaller sessions than usual on July 8 and 9. We are waiting to hear how many people will be allowed for each session before making a registration page. Other IPM and topic specific field days are in the works.


Dr. Lily Calderwood,
Dr. Seanna Annis,
Dr. Phil Fanning,
Wild blueberry technicians and graduate students