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POLLINATION INFO SHEET
BLUEBERRY
Pollination strategy for blueberry
POLLINATION INFO SHEET
BLUEBERRY
SUMMARY
Bumblebees are efficient at pollinating blueberries, with activity at lower temperatures than honeybees, faster visits
to flowers and higher rates of pollen transfer each flower visit. All this resulting in higher levels of fruit set with large,
evenly-ripening berries.
BENEFIT YOUR HEALTH
Blueberries contain anthocyanins, which give the berry its characteristic blue colour. This molecule has a good
effect on the cardiovascular system, by reducing cholesterol accumulation in blood vessels. In addition, blueberries
contain antioxidants, which play a role in slowing the aging process, work anti-inflammatory and protect against
various diseases, such as cancer.
FLOWER MORPHOLOGY
The flower colour is white-pink. The petals join to form a corolla tube which hangs downward. Pollen is produced
inside the anther, and must be released through a pollen pore at the very end. The style extends far below the
anthers, and is receptive only at the stigma.
Blueberries bloom in bunches and there is a big difference in flowering time between the first and the last flowers
of a bunch. Flowering season is during early spring.
FRUIT CHARACTERISTICS
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Efficient pollination contributes to better fruit quality.
The main characteristics of a good quality berry are:
 fruit size and weight, which is related to the number of seeds
 intensity and uniformity of berry’s blue colour
 flavour and crunchiness of the berry
post-harvest longevity
Biobest Belgium NV | Ilse Velden 18 | B-2260 Westerlo | tel.: +32 14 25.79.80 | fax: +32 14 25.79.82 | [email protected] | www.biobest.be
POLLINATION INFO SHEET
BLUEBERRY
WHY CROSS POLLINATION?
High-bush blueberries are self-fertile, but the produced berries will be small, slow to ripen, may drop off, and most
are considered to be none marketable.
Blueberries benefit considerably from cross-pollination, resulting in larger, evenly-ripening fruits and better yields.
Cross-pollination refers to pollen transfer between cultivars of the same species and is achieved by honeybees and
bumblebees while they fly from row to row. However, blueberries benefit significantly more from bumblebee buzzpollination.
BENEFITS OF USING BUMBLEBEES
Bumblebees are very efficient at pollinating blueberry:
 At lower temperatures
Bumblebees are active at lower temperatures (+/- 5°C). In contrast, honeybees
stop pollinating when conditions are colder than 10-15°C.
 During dark and cloudy days
Bumblebees use certain markings within their field of vision to orientate and
therefore dark and cloudy days will influence their flight activity less. Honeybees rely
mainly on the intensity of day light and the position of the sun for their orientation.
Consequently, bumblebees fly longer during the day than honeybees. They work
earlier in the morning and later in the evening.
 In covered crop
In plastic tunnels and greenhouses, bumblebees have been used for pollination
for decades. Although honeybees are closely related with bumblebees, they
do not perform well as pollinators because of diffuse light interfering with their
orientation capabilities. Bumblebees are less affected under these conditions.
 Low flower rejection
Bumblebees visit flowers primarily to collect pollen, which influences less their
flower selectivity, resulting in better pollination coverage.
Honeybees are not always suitable for pollination of all blueberry varieties, because
flowers may not be attractive enough for them due to the relatively low nectar
content.
 Faster and shorter flower visits
Biobest Belgium NV | Ilse Velden 18 | B-2260 Westerlo | tel.: +32 14 25.79.80 | fax: +32 14 25.79.82 | [email protected] | www.biobest.be
POLLINATION INFO SHEET
BLUEBERRY
Bumblebees are able to buzz-pollinate. They grab onto the flower and move
their flight muscles rapidly, causing the flower and anthers to vibrate, dislodging
pollen. This results in faster and shorter flower visits. Honeybees are not able to
buzz-polinate.
 Higher pollen transfer, fruit set and harvest.
90
80
70
60
50
40
30
20
10
0
Fruitset (%)
bumblebees
Pollen grains deposit per visit
honeybees
Due to its furriness and larger body size, bumblebees transport more pollen grains
and have optimum contact with the flower’s stigma. This results in a higher pollen
transfer and higher fecundity, which benefits fruit set and number of harvestable
fruits.
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 Fruit size and weight
As a consequence of better fecundity, bumblebee pollination increases the
proportion of larger fruits, both in size and weight, resulting in more uniform
production.
 Earlier harvest
Some testimonials of growers suggest that harvesting can begin 10 to 14 days
earlier by using bumblebees. Ripening of berries is more consistent over time; in
the past, you really had to look for ripe berries during the first weeks.
Biobest Belgium NV | Ilse Velden 18 | B-2260 Westerlo | tel.: +32 14 25.79.80 | fax: +32 14 25.79.82 | [email protected] | www.biobest.be
POLLINATION INFO SHEET
BLUEBERRY
POLLINATION ADVICE
For fruit and berry pollination we recommend 2 types of bumblebee hives.
Premium hive
Multi-Hive
Amount of
workers per hive
More than 110
3 outdoor colonies,
more than 350
Activity span
6-8 weeks
4-6 weeks
 Dosage
In open field, introduce 6-9 Premium hives or 2-3 Multi-Hives per hectare.
In plastic tunnels and greenhouses, Biobest advises to introduce bumblebees
at a rate of 1 Premium Hive per 750 – 1,000 m² or 3-4 Multi-Hives per
hectare.
REMARK: consult your local Biobest advisor to setup an adapted
pollination strategy.
 Timing
Introduce when 5-10% of plants are in bloom.
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 Hive placement
Spread around the field to maximize floral visitation, with a maximum of 250
meters between hives.
Place the bumblebee hives approximately 0.5 m above the ground, on a horizontal
surface. If necessary, protect hives against ants.
If hives are placed outside, use the Biobest Multi-Hive or make sure they are
protected from wind, rain, cold and direct sunlight.
Place with entrance(s) facing the sunny side. This will encourage even earlier
activity as the hive warms in the morning sun.
In some regions, it may also be necessary to protect hives against some animals
by using a fence.
If honeybees are used, place the bumblebee hives well away from honeybee
hives, as honeybees may benefit from the Biogluc inside the bumblebee hives.
 Pest management during pollination
To protect bumblebees do not apply broad-spectrum insecticides when blueberry
flowers are open. By monitoring for pest problems carefully before and during
bloom, growers can help minimize the need for pest control. If an insecticide
application is necessary, compounds that are least toxic and have a short
persistence should be used.
Before any application, lock-up the bumblebees using the bee-lock and remove
according the recommendations in the Biobest side effect list (www.biobest.be).
Contact your Biobest advisor for more information.
Biobest Belgium NV | Ilse Velden 18 | B-2260 Westerlo | tel.: +32 14 25.79.80 | fax: +32 14 25.79.82 | [email protected] | www.biobest.be