No Advantage to Dispersing Bee Colonies in Blueberries

Preliminary data from two years of a multi-year, multi-region study has found no advantage to dispersing bee colonies in a blueberry field, and in fact may be a disadvantage, according to a presentation at the Oregon Blueberry Conference from Oregon State University Extension pollination health expert Andony Melathopoulos.

Andony Melathopoulos in a presentation at the Oregon Blueberry Conference in Salem in February, said two years of data has shown no advantage to dispersing over clumping bee colonies in blueberries.

In testing whether there was an advantage to dispersing colonies in field trials, researchers walked rows and counted bees on flowers. In addition, individual bushes were bagged to prevent bees from pollinating berries and some branches were hand pollinated.

Researchers then counted seeds per berry and berry weight to help determine if there was a benefit to dispersing colonies. The findings, that berries in field sectors with clumped colonies actually seemed to do better than berries in sectors with dispersed colonies, were consistent across Oregon and Washington, Melathopoulos said.

Melathopoulos added that beekeepers prefer clumping colonies over dispersing them.

“If you ask any beekeeper, it increases their labor costs (to disperse colonies), because they have to get in and out of the truck between each one of those drops,” Melathopoulos said.

Also, he said, there is a thought among beekeepers that dispersing colonies in a field can more readily expose bees to pesticides. “So, it causes more irritants with the beekeepers,” Melathopoulos said.

Researchers plan to continue investigating the findings. “This work is being repeated in Michigan, Florida and Washington, and hopefully we can see if there are some trends,” he said.

Conducted over 2021 and 2022, the research is part of an overarching project to develop a blueberry pollination planning tool that gauges pollination needs in any one year based on weather forecast, cultivar and other factors.

“Something like this currently exists for apples,” Melathopoulos said. “We are interested in making this blueberry specific and adding things like blueberry cultivar, colony stocking rate and colony strength. So, like for apples, but better and for blueberries.”