Cooperative Extension: Maine Wild Blueberries

4.29.16 Weather Station Link, Cold Temperatures & Upcoming Possible Infection period

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Weather Stations Link

Here is the link to the weather station website: Maine Blueberry Weather Stations 2016 (AgriNet University of Maine Blueberry Disease Model Data Dashboard website)

The first page shows our latest date for a weather station and graphs showing weather parameters for all of the weather stations.  If you click on the “Downloader and Graphs Page” link it will take you to a page showing graphs for each weather station.

Cold Temperatures

We have been having cold temperatures in our monitored blueberry fields in the last few nights.  Blueberry flowers at the stages I have seen in blueberry fields this week are not far enough along to probably suffer much damage due to cold.  At flower bud stage F1 to F4 (Fact Sheet 216 – Flower Primordia Development Stage), flowers are still very cold hardy and while each clone will vary in resistance to cold temperature, they can cope with temperatures from 4ºF  to about 10ºF.   I have attached a chart with the coldest air temperature in the blueberry canopy we have observed in the last two nights for your information.

Upcoming Infection Period

Plants throughout blueberry growing areas probably have enough susceptible buds (over 40% at F2) and pinheads and cups have been found throughout blueberry growing areas.  The rain coming in on Sunday through Monday night is likely to cause an infection period for mummy berry in most fields.