How to pollinate raspberries with bees

Pollination of raspberries by honey bees

Raspberries are one of the most common berry plants in Europe and North America. Suffice it to say that 778,405 tons of raspberries are produced worldwide every year.

List of countries by raspberry production 

Country	Production (Tons)	Production per person (kg)	Area (ha)	Yield (kg/ha)
Russian Federation	164 602	1,121	21 025	7 829
United States of America	137 829	0,421	8 765	15 724,9
Poland	129 063	3,358	29 282	4 407,6
Mexico	112 661	0,903	6 208	18 147,2
Serbia	61 875	8,837	11 041	5 604,1
Ukraine	31 920	0,755	4 600	6 939,1
Bosnia and Herzegovina	22 160	5,856	2 647	8 371,7
Chile	19 132	1,089	4 783	4 000
Spain	17 808	0,382	1 801	9 886,2
UK	14 908	0,226	1 552	9 605,7

 A lot of raspberries are grown in countries such as Bulgaria, Germany, France, Italy, Azerbaijan, Canada, Australia.

Therefore, farmers are interested in obtaining a high quality raspberry crop and in a larger volume. Pollination of raspberry flowers by bees will help improve the presentation of raspberry fruits and increase the yield.

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The role of bees in raspberry pollination

The raspberry flower has a double perianth. Five green sepals form a calyx, and five petals form a corolla.

In the center of the flower are numerous pistils surrounded by rings of stamens. Usually, in raspberries, part of the pistils is located above the stamens, and the ingress of pollen on the stigma of these pistils without the participation of insects is difficult. A multi-petal and multi-stamen raspberry flower can be pollinated by its own pollen, but pollination is best done with the participation of insects, since the sticky heavy raspberry pollen is not carried by the wind, and the columns in the flowers are much longer than the stamens.

Raspberries have a complex fruit - a drupe. In a complex raspberry fruit, each individual fruit can develop only as a result of the fertilization of a separate ovary. Therefore, with a lack of pollinating insects, only a part of the flower ovaries is fertilized, resulting in small, underdeveloped, irregularly shaped fruits of low quality. An ugly raspberry has a lower weight and an unattractive (non-marketable) appearance. The reasons for the ugliness of berries can be varied, but all or almost all of them are the result of poor pollination. The fact of incomplete setting of drupes in raspberries during self-pollination does not allow us to confidently classify existing raspberry varieties as completely self-fertile. Specially set experiments revealed that the role of wind in cross-pollination of raspberries is insignificant. Therefore, raspberries require cross-pollination, which is carried out mainly by honey bees.

Pollination of a raspberry flower by bees ensures an abundant application of pollen to the stigmas of all pistils and guarantees the normal development of the berry, i.e., the setting of all drupes.

Thus, pollination of raspberry flowers by bees is a mandatory technique for growing raspberries, along with other agricultural practices.

How many bees does it take to pollinate a raspberry?

For full pollination of raspberry flowers by bees, it is important to create the desired density of bees per unit area. How many bees should pollinate raspberries? On raspberry plantings, 30-40 bees per 10 square meters should work at the same time. This means that in order to pollinate raspberries normally, it is enough to take out 2 bee colonies per 1 hectare.

What is important to consider when pollinating raspberries by bees

When organizing raspberry pollination, it must be taken into account that raspberries, as a rule, bloom 10 days later than other berry crops, and bloom for at least 15 days.

The bees are very willing to visit raspberries, as raspberry flowers produce a lot of nectar. For this reason, it is not necessary to train bees to pollinate raspberries.

Given that raspberries are a good honey plant, the installation of a pollen collector can have a negative effect on the flight activity of bees.

To increase the pollination activity of bees, the following measures can be applied:

• Remove bee bread from the hive.
• Use strong bee colonies for raspberry pollination.
• Families should have brood of different ages.
• Bring the hive as close as possible to planting raspberries.

The implementation of these recommendations will allow you to get a big harvest of raspberries.