In order to create fruit, wild blueberries depend heavily on
insects, especially honeybees, for pollination. While this relationship for achieving pollination is largely successful,
there can be problems. In fact, a lot can go wrong during bloom
resulting in less-than-optimal pollination. In this blog, we are going to be
talking about some pitfalls, as well as good practices related to wild
blueberry pollination.
Some thoughts on wild blueberry pollination!
Eastern Canada’s wild blueberries are a
mostly managed lowbush, native species (Vaccinium angustifolium) which
produce fruit commercially. The flowers of this species can be difficult to
pollinate for some insect species. Tightly clustered and hanging like small bells,
blueberry blossoms prefer to only release pollen when buzz pollinated. This is achieved by bees using a process
called sonication to release the pollen as they visit the bloom. This is best done by bumble bees, with the
primary pollinator, honey bees, moving pollen passively as they visit the
blossoms collecting nectar. Thousands of
honey bee colonies are brought into our region, for commercial wild blueberry
production each season, as their sheer numbers create a tremendous pollination
workforce.
Pollination, although perhaps sounding like a simple process,
is delicate with multiple steps. In spite of applying managed pollinators to
blueberry fields there are factors which may prevent optimal pollination. Signs
of things going wrong may include poor fruit set, small berries, delayed
ripening, and sometimes whole parts of fields under producing.
Optimal timing and placement for pollination is a challenge to achieve for both blueberry producers and beekeepers. The timing of blueberry bloom, highly dependent on temperature and sunlight, can shift dramatically depending on the year and location. Bees meanwhile are moved in based on scheduling and availability. If colonies arrive too early, they may undergo nutritive stress or habituate to other floral sources. If placed too late, the optimal bloom window for pollination may be missed. Even with perfect timing, weather can have a detrimental impact on pollination. Rain, cold, and wind will all reduce activity as honey bees do not forage well below 13–15°C3 and during periods of precipitation.
Hive health and overall strength are important determinants
of pollination success. Hives should meet the established pollination
standard2 for
wild blueberry pollination in the Maritime region. A lesser understood factor could be transport
stress as well as, pests and diseases can leave colonies underperforming.
Agrichemical exposure may also have detrimental impacts on managed pollinators. Most blueberry producers are aware of the potential harm to pollinators and will avoid spraying while bees are on the bloom. All stakeholders are encouraged to follow best practices and familiarize themselves with guides like “Protecting Pollinators from Pesticides – Wild Blueberry.” This publication, produce collaboratively between ATTTA and the Pollination Partnership, is available online.
Field access and optimal placement will also impact
pollination success. Beekeepers need to
access field locations in order to distribute the colonies evenly. Even though
honey bees will travel considerable distances to forage, it is best to avoid clustering
all the colonies in one area or placing them too far from dense patches of
bloom. Better placement equals better coverage which equals better pollination
2
Another limiting
factor in achieving optimal pollination is the supply of bees. By times, there may not be adequate numbers
of managed pollinators. This limitation
can be for any managed pollinator including honey bees, bumble bees or alfalfa
leafcutter bees. The number of
pollination units available varies, due to many factors, seasonally, but the
industry is working to increase the supply which has already had positive
impact on the availability of pollinators.
It is the strategic goal of the industry to increase the pollination
capacity of our region with steps already being taken to secure an adequate
supply.
It must be remembered that managed bees are not the only pollinators, with native species like bumble bees and solitary bees, contributing to pollination success. These insects are especially important for pollination during the initial bloom, when temperatures are low, and on poor weather days when honey bees are reluctant to fly. So, properly managed bees as well as native insects play an important role in ensuring consistent and well pollinated fields.
Written by Gregory Dugas, 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 attta@perennia.ca
References
1. 1. Eaton, L.J. and Nams, V.O., 2012. Honey bee
stocking numbers and wild blueberry production in Nova Scotia. Canadian Journal
of Plant Science, 92(7), pp.1305-1310.
2.
2. Bennett, A. and A. Byers. 2023. Best
Management Practices Guide for Honey Bee Pollination of Wild Blueberries in
Atlantic Canada. Atlantic Tech Transfer Team for Apiculture
3.
3. Dugas, G. (2023) Honey Bee and Bumble Bee Pollination, ATTTA Buzz, 13 July.