Former Program Coordinator, Horticulture
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Thursday, December 3, 2015
The University of Minnesota Extension hosted a webinar on Dec 1 entitled "Mitigating Pollinator Decline in Landscapes" that was very informative. The pdf of the presentations and the videos will be posted by Dec 10, 2015 at learn extension website. The remainder of this article summarizes the key points of the session.
There are over 4000 species of native bees in North America. Nearly 90% of native bees are solitary unlike honey bees that live in large perennial colonies. The nesting habits of wild bees are quite different than honey bees with 70% nesting in the ground and 30% nesting in plant stems, rotting wood, and standing dead trees. Native bees depend almost exclusively on flowers for their full life cycle and they are significant for native plant and crop pollination.
Approximately 1/3 of the human diet is sourced by bee pollinated crops. If all bees were gone, it would decimate the fruit and produce section of the supermarket.
Mitigating pollinator decline comes down to delivering the following things that bees need:
- Good nesting sites
- Forage for nutrition
- A safe environment
Our garden practices can dramatically impact bees. Cutting plant material down in late spring and leaving stem stubble provides good nesting sites. Maintaining areas of bare or sparsely vegetated loose soil allows bees to dig and create nests so minimize the use of mulch where possible. Positioning tree logs and rocks among your garden plants also improve the habitat for nesting sites.
Look for nest entrances in early spring to identify where bees are nesting. A ground bee nest looks similar to an anthill, but with a larger opening.
Ensuring pollen and nectar rich flowers are blooming throughout the season provide a steady diet for the bees. Flowers that every pollinator friendly garden should have include:
- Bee balm (Monarda fistulosa)
- Anise hyssop (Agastache foeniculum)
- New England aster (Symphyotrichum novae-angliae)
- Goldenrod (Solidago species)
Practice integrated pest management in your garden. Use a combination of management techniques to reduce pests naturally and rely on chemicals only as a last resort. Always check the non-target organisms that your chemicals affect and follow application directions to the letter. Also avoid systemic pesticides.
A combination of factors are negatively impacting bees:
- Parasites attacking bees
- Queen loss
- Pesticide drift
- Loss of foraging resources to excess turf and loss of CRP land
- Genetic diversity and vitality loss among honey bees
The webinar featured Dr. Dan Cariveau, Assistant Professor University of Minnesota, on native bee populations; Dr. Karl Foord, Extension Educator, University of Minnesota, on IPM for bees; and Ms. Heather Holm, Author and restorationist.
Photo Above Right: Xerxes Society