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ARS Home » Southeast Area » Poplarville, Mississippi » Southern Horticultural Research » Research » Publications at this Location » Publication #115815

Title: EVALUATING BUMBLEBEES AS POLLINATORS OF 'MISTY' SOUTHERN HIGHBUSH BLUEBERRYGROWING INSIDE PLASTIC TUNNELS

Author
item Sampson, Blair
item Spiers, James

Submitted to: Acta Horticulturae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/30/2002
Publication Date: 4/30/2002
Citation: Acta Hort.574.ISHS 2002 pgs. 53-61. Proc. 7th IS on Vaccinium

Interpretive Summary: Pollinating southern highbush blueberries in small greenhouses or tunnels requires a bee species both adapted to tunnel conditions as well as have an exceptional ability to forage at the deeper blossoms of blueberry plants. One bumblebee species satisfies these two criteria. A commercially reared bumblebee that lived inside a plastic hive box foraged well within the limited space of plastic tunnels. This bumblebee also has a powerful homing instinct that allows the worker bees to be rounded up in the evening and moved to another tunnel for blueberry pollination. Workers have long-tongues that can reach the nectar deep inside the bell-shaped flowers of blueberry. Workers also buzz-pollinate these flowers to shake pollen loose thereby greatly enhancing the ability of a bumblebee to efficiently pollinate a blueberry crop. Bumblebees pollinate blueberries best when tunnels are kept cool below 30 deg C, and flowers are dry. To fully take advantage of bumblebee pollination, two or more different varieties of southern highbush blueberries must be placed inside tunnels. Varieties can be arranged inside the tunnels so that for each plant providing compatible pollen, five other plants from the more desirable varieties will bear marketable fruit.

Technical Abstract: Commercial bumblebees pollinating elite hybrid varieties of southern highbush blueberries growing inside plastic tunnels can help increase the market value for blueberry fruit. A bumblebee colony, rotated to a new tunnel every 2-3 days, cross-pollinated two compatible varieties of southern highbush blueberries planted in the approximate ratio of 13 'Misty': 1 'Sharpblue'. Colony rotation between tunnels provided more bloom to the bees and eliminated buying a bumblebee colony for each tunnel. Plastic tunnels protected the bumblebees, flowers and developing fruit from freezing during the late winter in southern Mississippi. Bumblebees improved 'Misty' fruit production and quality in tunnels, as their visits to flowers substantially enhanced fruit set, ripening, berry size and seed set. Unpollinated 'Misty' flowers produced some parthenocarpic fruit. A more efficient cooling system for tunnels, changes in frost protection systems and/or placing colonies outdoors on warmer days will be needed to sustain uninterrupted pollen foraging and pollination by worker bumblebees. Other native bee pollinators such as the megachilid bee, Osmia ribifloris, may soon be available for pollinating blueberries inside tunnels.