Field Notes: Honeybee Plight

MAN DOES NOT LIVE BY BREAD ALONE, and, therefore, we need bees. We especially need the European honeybee, Apis mellifera, which, by virtue of its colonizing habits, portability, and talent for effectively pollinating a wide range of crops, is relied upon by American agriculture more than any other pollinator to ensure fruit development in billions of dollars’ worth of apples, peaches, melons, and other crops every year.

But the honeybee is in trouble. I first began to suspect this one sunny May afternoon in 1996, when my husband and I were accompanying friends on a picnic on a farm in south-central Tennessee. As we crossed a pasture carpeted in clover, I noticed the bees were missing. Those thousands of puffy white clover blossoms should have been churning with worker bees, but there were none. Not one.

I soon learned that wild honeybee populations across the country had virtually vanished, and beekeepers were struggling to protect their colonies from two species of deadly parasitic mites. The varroa mite, Varroa jacobsoni –originally a parasite of the more resistant Asian honeybee, A. cerana– has rapidly spread throughout the continent since it was first discovered among European honeybees in two U.S. states in 1987. An easily transmitted, external parasite the size of a pinhead, this mite attaches to adult bees and sucks their "blood"; young mites, in turn, feed on bee larvae. Of uncertain origin, the microscopic tracheal mite Acarapis woodi attaches to the inside of the bees’ air passages, blocking air flow to the wing muscles and rendering the affected bees unable to fly. Either pest can rapidly destroy a colony.

Fluvalinate, a pyrethroid chemical marketed under the name Apistan, is used by beekeepers to combat the varroa mite, but in some locales the mite is showing resistance, possibly because the chemical has been misused. Coumaphos, a livestock insecticide, is a new option available by emergency permit. Some beekeepers, meanwhile, are hopeful that concoctions of wintergreen and other essential plant oils will prove effective against varroa mites. Menthol kills tracheal mites, and apiarists can purchase a strain of honeybee developed in England known as Buckfast that is resistant to tracheal mites. So far, efforts to produce a satisfactory bee with resistance to varroa have shown a mixture of promise and disappointment.

The plight of the honeybee may or may not affect fruit set in your home garden. "In some areas alternative pollinators, such as bumblebees or the native squash bee, are sufficient; in others they aren’t," says John Skinner, associate professor of entomology and plant pathology at the University of Tennessee at Knoxville. "Having colonies of honeybees near your garden is excellent insurance." Dr. Skinner recommends that you attract honeybees and other pollinators by planting nectar sources such as salvias and other mint family members, sunflowers, and buddleias. "Try to have something in bloom all season."

He advises caution with insecticides. "Misuse of chemicals in a home garden is a big concern of mine. Observe your garden and don’t apply chemicals when the bees are there. With vine crops, such as squash and melons, for example, apply chemicals when the flowers are closed. If the bees visit in the morning, spray in the late afternoon." Since dusts are especially risky to bees, he suggests formulations with sticking agents that make the toxin adhere to the plant. Use the least toxic chemicals available, selected from the list of chemicals and their toxicity rates supplied by your county agent.

To ensure pollination, consider keeping bees yourself if you don’t already. Consult your cooperative extension service or nearest botanical garden or contact the American Beekeeping Federation, P.O. Box 1038, Jesup, Georgia 31598-1038; 912-427-8447. Your personal promised land may not be zoned for milk cows, but even the smallest city garden can be made to flow with honey.

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