Buckeyed Bees

Jun 1, 2010

Danger: Poison ahead.

Beekeepers do not like the California Buckeye (Aesculus californica).

Honey bees do, but they shouldn't.

It's poisonous to bees.

The California Buckeye, which grows as either a tree or a shrub 10 to 20 feet tall and can sprawl 30-feet wide, blooms in the spring. its candelabralike clusters of fragrant cream-colored blossoms attract hummingbirds, butterflies and bees.

About a week after honey bees work the blossoms, however, symptoms of buckeye poisoning appear in the hive.

"Many young larvae die, giving the brood pattern an irregular appearance," according to the booklet,
Beekeeping in California, written primarily by a team of UC Davis entomologists and published in 1987 by the UC Division of Agriculture and Natural Resources. "The queen's egg-laying rate decreases or stops, or she may lay only drone eggs; after a few weeks, an increasing number of eggs fail to hatch or a majority of young larvae die before they are three days old."

What occurs: "buckeyed bees."

"Some adults emerge with crippled wings or malformed legs and bodies," wrote authors Eric Mussen, Norman Gary, Harry H. Laidlaw Jr., Robbin Thorp and Lee Watkins of the UC Davis bee biology program and Len Foote, then with the California Department of Food and Agriculture. 

And, of course, with deformed wings, the bees cannot fly.

Buckeye poisoning can result in seriously weakened colonies or colony death.  The authors also point out that "foraging bees feeding on buckeye blossoms may have dark, shiny bodies and paralysislike symptoms."

Solution: move the bees away from the buckeyes.

California Buckeye, according to the Sunset Western Garden Book, is "native to dry slopes and canyons below 4000-foot elevation in Coast Ranges and the Sierra foothills."

It is quite common along Pleasants Valley Road in Vacaville (Solano County), Calif. If you cross the picturesque country bridge, the Edward R. Thurber Bridge, you'll see it.

And honey bees foraging among the blossoms.


By Kathy Keatley Garvey
Author - Communications specialist

Attached Images:

CALIFORNIA BUCKEYE blooms along the Edward R. Thurber Bridge on Pleasants Valley Road, Vacaville. The sign says

Edward R. Thurber Bridge

HONEY BEE forages on the fragrant blossoms of the California Buckeye. Bees are attracted to the plant, but it is poisonous to them. (Photo by Kathy Keatley Garvey)

Foraging Bee

FORAGING on California Buckeye, this honey bee is oblivious of what this can do to her colony. California Buckeye is poisonous to bees. (Photo by Kathy Keatley Garvey)

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