2023 Updates and Seasonal Outlook for NS_ June 9

Friday, June 9, 2023


Nova Scotia Weather and Wild Blueberry Crop Development Updates


Here are some newest updates on weather and wild blueberry crop development in Nova Scotia.


2023 Degree Day Accumulations- based on Kentville Weather Stations

Cumulative degree days continue to be slightly behind the 5- and 10-year averages for plant and insect development (Figure 1).

Figure 1: Heating degree day accumulations for plant (above 5°C) and insect (above 10°C) development from March 1 to May 29 for the past 17 seasons. Provided by Jeff Franklin (AAFC).


Cumulative Precipitation- June 6- based on Kentville Weather Stations


Figure 2. Kentville Weather Station Precipitation Update- June 6. Provided by Jeff Franklin (AAFC).


I am sure many of us were happy to see the rain we got in the first few days of June. The amount of rain we got since June is certainly helpful, especially for pollination. After the rain, I also noticed more damage symptoms from herbicides starting to show. However, this rain and the heat might bring more diseases, such as Botrytis.  


Soil temps- June 6- based on Kentville Weather Stations

Figure 3. Soil temps- June 6. Provided by Jeff Franklin (AAFC).


It is not surprising to see that the plant development slowed down after mid-May and we didn’t experience super early blooms for most of the central fields. It was dry and the soil temps stayed around a 10-year provincial average. Since the beginning of June, soil temps started to decrease and fall below the average. In the last few days, plant development was a bit slower but expect things will start to pick up after the rain we got and more summer hot days we are going to get.


Nova Scotia Wild Blueberry Crop Development Updates


Here are the latest wild blueberry weather stations’ GDDs.


Figure 4. Wild Blueberry Weather Stations GDDs- June 8

Crop fields:


-          Early fields (Southshore counties, early fields in Cumberland) are in full bloom and are towards the end of this year’s pollination. A good percentage of petal fall (pin head) was observed in those fields. Those fields should only need another could of good weather days to make things look great in July! I don’t have further recommendations for those fields until blueberry maggot and SWD season. Growers should start to look for monitoring materials though.





-          Central fields: fields in the central areas start to catch up with those early fields. Bees should be placed in those fields now. The next two weeks’ weather would be critical for those fields. If you have had a Botrytis issue in the past or a wet/foggy area, you are still under the susceptible period. Please consider approved fungicides to be applied in this crop stage.


-          Fields in Pictou, Antigonish and Cape Breton: mostly in pre-bloom (Cape Breton) and early to mid-blooms (Pictou and Antigonish). Growers can start with their bumble bees but start to talk to your bee suppliers. Beehives should be in those fields fairly soon.



Sprout fields:


We are looking at in-between 50% to 70% plant emergence across the province.


During this time of the year, activities can be and should be done in sprout fields including weed management and applying fertilizers. Growers can pull or cut weeds above the blueberry canopy before they go to seed or cut weeds to the base. If it is necessary, some selective post-emergent herbicides, such as Callisto 480 SC (mesotrione) can be used to control a wide range of broadleaf weeds.

Here is a little bit of information about using Callisto to achieve effective weed management.

Blueberry growers have observed more crop injury when applications are made under hot and/or humid conditions or when the crop is stressed from flooding. The injury is most visible where excessive rates have been applied, such as sprayer overlaps. If heavy rain is expected within 48 hours, an application should be delayed. For improved crop safety, make applications under cooler conditions (early morning or evening) or when daytime temperatures are below 21 °C.


Please check your beehives and bumblebee boxes! Bears smell blueberry blooms!


Over the last few days, I heard a few stories about bears tearing bumblebee boxes and I also saw a few damaged bumblebee boxes when I was travelling over the last few days


It is the time of the year. They can smell blueberry flowers and they know where to find good stuff! Please check and secure your hives and boxes.