Pollination in pear: bumblebees can do the job!

Pollination is one of the critical success factors in pear production. With cold weather during the flowering season like this year, reliance on natural pollinators and even honeybees is usually insufficient to guarantee good fruit set. Many pear growers routinely spray plant hormones to promote fruit set. Biobest has used the 2013 season to work with commercial pear growers in Belgium to test, develop and demonstrate the potential of bumblebee pollination.

 
Pollination requirements in pear differ according to the cultivar. The cultivar Doyenné du Comice is not self-fertile. Therefore, cross-pollination is mandatory to achieve successful fruit set. Conference, in contrast, is self-fertile and does not strictly depend on cross-pollination. Nevertheless, Conference also benefits a lot from insect (cross) pollination, resulting in larger fruits. Thus, in spite of these biological differences, both Doyenné du Comice and Conference benefit strongly from active insect pollination.


Nevertheless, it is not a routine practice for pear growers to bring bees into their orchards to promote pollination. While honeybees have been used occasionally, pear growers are not familiar with the use of commercial bumblebees in their orchards. Some are even outright skeptical about a bumblebee’s ability to pollinate pear flowers.


During the 2013 season, we, together with Veiling Borgloon, set up a comparison between plots with the growers’ standard treatment (hormone spraying, no introduction of pollinator insects) with plots in which bumblebees were introduced at a rate of 10 colonies per ha. This resulted in convincing benefits in terms of fruit set and in a clear advantage in terms of size of the growing fruits. Full results with the analysis of fruit caliber and quality will be reported at the end of the season.


While testing and demonstrating the impact of introducing bumblebees, we took things a step further and also evaluated the potential of Biobest’s latest bumblebee technology, the Flying Doctors^®. Flying Doctors^® hives come equipped with a special dispenser in which one can introduce, for example, microbial products for disease control and have them delivered directly to the flower by the bumblebees. But the dispenser of a Flying Doctors^® hive can also be filled with pollen. Pollen of certain pear varieties is commercially available. Rather than spraying or dusting the precious pollen, which some top growers actually do today, what is more effective than having it delivered by a dedicated pollinator insect right to where it is needed? Again, results in terms of pollen consumption, fruit set and size of the growing fruits made a few growers with whom we are collaborating very, very excited. Keep watching your Biobest newsletter in the coming months for a full report.