Wild blueberries are managed on a two-year production cycle, meaning that the plants need to grow for two years for a harvestable crop. During this time, wild blueberry floral buds need to go through three dormancy stages before flowering. Please see previous blogs for more detailed information on the first two dormancy stages, para- and endo- dormancy. Once the blueberry buds have met their para- and endo-dormancy requirements they can enter ecodormancy, which is normally late winter to early spring. Once ecodormancy requirements have been met, then the buds will flower. Wild blueberry producers currently use ecodormancy requirements, based on growing degree days (GDD), to try and predict when the buds will open, and pollinators are needed in the fields. Knowing the requirements that are needed for ecodormancy could help with predicting wild blueberry bloom and allow for more precise placement of managed pollinators for more efficient use of this limited resource.

Wild Blueberry Phenology in the Crop Year - Ecodormancy

Ecodormancy is the second winter dormancy stage of floral buds, where the reaction leading to growth control is driven by external environmental cues, such as warm temperatures⁵. Ecodormant buds will not flower normally, meaning that only some of the buds will open when placed in growth adequate conditions, and the ones that do open will take longer to do so. Ecodormancy will prevent the floral buds from opening until the growing conditions are adequate for flowers, therefore protecting them from fluctuating conditions in the spring. Ecodormancy release relies on an accumulation of warm temperatures and the most common way of measuring the accumulation of warm temperatures is with GDDs⁵.

Ecodormant wild blueberry floral buds in early Spring (© John MacDonald 2024)

GDDs are a measure of accumulated daily heat units during which the plant has potential to be physiologically active and is measured using daily mean temperatures¹. Accumulations of heat units for ecodormancy begin when endodormancy is released. Currently, there are limited experimental results for when endodormancy is released for wild blueberries. Therefore, GDD accumulations for ecodormancy begin at a selected calendar date³, which is currently April 1^st for wild blueberries. Most GDD models include a base and upper temperature threshold, specific to different organisms, at which development may be delayed due to unfavorable growing conditions³. GDD models can be used to predict many crop phenological events, such as pest life cycles for applications of pesticides and floral bloom for placement of pollinators.

GDD models have been created in Nova Scotia to predict phenology of weeds, such as yellow toadflax (Linaria vulgaris), spreading dogbane (Apocynum androsaemifolium), and red sorrel (Rumex acetosella)^2,9,10. GDD models have also been created for predicting flowering in highbush and lowbush blueberries^4,6. More specifically, wild blueberry ramet emergence, tip-dieback, and flowering prediction models have been created in Nova Scotia⁸. The existing model for wild blueberry flowering, however, requires revisions to include early flowering wild blueberry genets and the timing of endodormancy release.

Wild blueberry field during ecodormancy in early Spring (© John MacDonald 2024)

Perennia Food and Agriculture Corporation, Nova Scotia’s technical food development agency, currently has an application called Farm Weather on the Farm Data Tools Website. This tool will easily calculate GDD accumulations at weather stations, including 55 on wild blueberry fields, throughout Nova Scotia. Please make an account on Farm Data Tools and check out this very useful resource (Farm Data Tools – Farm Data Tools).

The placement of pollinators on wild blueberry fields during bloom can be difficult to plan. Learning more about the phenology stages of wild blueberries, such as endo- and eco-dormancy requirements, may help to create predictive models for the placement of pollinators. These models, based on GDD, could allow more efficient use of managed pollinators, improve wild blueberry production, and support honey bee health.

Written by John MacDonald, ATTTA Seasonal Apiculturist

Connecting with ATTTA Specialists

If you’d like to connect with ATTTA specialists or learn more about our program, you can:

visit our website at https://www.perennia.ca/portfolio-items/honey-bees/

Email abyers@perennia.ca

References:

1. Baskerville, G.L. and Emin, P. (1969) ‘Rapid Estimation of Heat Accumulation from Maximum and Minimum Temperatures’, Ecology, 50(3), pp. 514–517. Available at: https://doi.org/10.2307/1933912.

2. Blatt, S., De Clerck-Floate, R. and White, S.N. (2022) ‘Development of a growing degree-day model to estimate Linaria vulgaris shoot emergence and prospects for improving biological control efforts’, Invasive Plant Science and Management, 15(1), pp. 9–15. Available at: https://doi.org/10.1017/inp.2022.6.

3. Carlson, J.D. and Hancock, J.F. (1991) ‘A Methodology for Determining Suitable Heat-unit Requirements for Harvest of Highbush Blueberry’, Journal of the American Society for Horticultural Science, 116(5), pp. 774–779. Available at: https://doi.org/10.21273/JASHS.116.5.774.

4. Kirk, A.K. and Isaacs, R. (2012) ‘Predicting Flower Phenology and Viability of Highbush Blueberry’, HortScience, 47(9), pp. 1291–1296. Available at: https://doi.org/10.21273/HORTSCI.47.9.1291.

5. Lang, G.A. et al. (1987) ‘Endo-, Para-, and Ecodormancy: Physiological Terminology and Classification for Dormancy Research’, 22.

6. NeSmith, D.S. and Bridges, D.C. (1992) ‘Modeling Chilling Influence on Cumulative Flowering: A Case Study Using `Tifblue Rabbiteye Blueberry’, Journal of the American Society for Horticultural Science, 117(5), pp. 698–702. Available at: https://doi.org/10.21273/JASHS.117.5.698.

7. Rieger, M. (2006) Introduction to Fruit Crops. Haworth Food & Agricultural Products Press.

8. White, S.N., Boyd, N.S. and Van Acker, R.C. (2012) ‘Growing Degree-day Models for Predicting Lowbush Blueberry (Vaccinium angustifolium Ait.) Ramet Emergence, Tip Dieback, and Flowering in Nova Scotia, Canada’, HortScience, 47(8), pp. 1014–1021. Available at: https://doi.org/10.21273/HORTSCI.47.8.1014.

9. White, S.N., Boyd, N.S. and Van Acker, R.C. (2015) ‘Temperature Thresholds and Growing-Degree-Day Models for Red Sorrel (Rumex acetosella) Ramet Sprouting, Emergence, and Flowering in Wild Blueberry’, Weed Science, 63(1), pp. 254–263. Available at: https://doi.org/10.1614/WS-D-14-00048.1.

10. Wu, L. et al. (2013) ‘Spreading Dogbane (Apocynum androsaemifolium) Development in Wild Blueberry Fields’, Weed Science, 61(3), pp. 422–427. Available at: https://doi.org/10.1614/WS-D-12-00156.1.

The wild blueberry and beekeeping industries depend on each other for continued growth. Despite being busy, the summer is a useful time for beekeepers and wild blueberry producers to have events to learn about what’s happening in these industries. The Atlantic Tech Transfer Team for Apiculture had the pleasure of attending the New Brunswick Beekeeper’s Association (NBBA) evening session last Saturday and the Wild Blueberry Producer’s Association of Nova Scotia’s (WBPANS) field day this past Wednesday. Continue reading for details on these great events!

NBBA Evening Meeting Summary

A group of New Brunswick beekeepers gathered for an evening meeting, entitled “Bees and Honey….From frame to barrel” on the evening of Saturday July 13^th. This event was put on by the New Brunswick Beekeeping Association and hosted by Chris Lockhart of Lockhart Apiaries and Atlantic Gold Honey. The event, held in the Moncton area, was well attended by over 20 local beekeepers, providing an excellent mid season opportunity for discussion. There were three short presentations across the evening. Chris Lockhart gave an overview of his operation and showed his extraction operation. The Atlantic Tech Transfer Team for Apiculture did a demonstration on honey quality, diversity and classification. Additionally, ATTTA talked about mid season disease management. Overall, a pleasant and well received industry event organized by the NBBA to support the New Brunswick beekeeping sector.

Chris Lockhart (center) discussing his beekeeping operation, flanked by prominent NB beekeepers, Eric Neil (left) and Boyd Hicks (right) at the recent NBBA evening meeting.

WBPANS 2024 Field Day

On July 17th, the WBPANS held their annual summer meeting, hosted by Paul and Lori Kittilsen at their beekeeping farm in the Debert area. The event began in the morning with tours and demonstrations around the Kittilsen’s farm. These included wild blueberry and beekeeping machinery demonstrations, an example of a pollinator strip, and tours through the Kittilsen’s honey extraction room, bottling room, and construction workshop.

Paul Kittilsen speaking at the WBPANS Annual Meeting

There were many exhibitors set up throughout the day to give demonstrations. There were equipment and machinery displays, where attendees could test drive forklifts and harvesters and shop for new equipment. There were displays and delegates from across the agri-business sector, including NS Crop and Livestock Insurance and Farm Credit Canada, as well as the chance to talk to government staff and industry representatives. Also, attendees could talk to wild blueberry researchers and representatives, including many researchers from Dalhousie University, Living Labs, and Perennia.

The Kilted Chef and his team provided a delicious wild blueberry themed lunch, during which there were presentations given. The WBPANS president, David Harrison, and executive director, Peter Burgess, of WBPANS welcomed the group and provided a WBPANS update. Hugh Lyu, the wild blueberry extension specialist at Perennia, provided an industry update looking at the season so far this year. Also, Paul and Lori Kittilsen introduced everyone to their team and gave an overview of their business and history as beekeepers and honey producers. The Kittilsen’s have nearly 2000 honey bee hives that go to wild blueberry fields for pollination, hugely contributing to the wild blueberry industry.

John and Kaitlyn from ATTTA with the Kilted Chef at the WBPANS Annual meeting

Thank you to all the members of WBPANS who helped organize this field day, and to all those who work to support the wild blueberry industry in Nova Scotia.

The next beekeeper event for our region the Atlantic Bee Tour held in Bathurst and Charlo on the 26 & 27 July. Details can be found on the NBBA web site: https://nbba.ca/

Connecting with ATTTA Specialists

If you’d like to connect with ATTTA specialists or learn more about our program, you can:
visit our website at https://www.perennia.ca/portfolio-items/honey-bees/
Email abyers@perennia.ca

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