The Pollinator Puzzle: IPM Experts Seek Keys to Honey Bee Health

Mapping the issue: Management practices, pesticides, varroa mites, and forage diversity are factors in bee health. Source: J. Pettis, USDA.

In 2006, managed honey bee colonies began to die off in large numbers without explanation. Scientists believe this problem may be caused by multiple factors, including disease, nutrition, genetics, parasites, pesticides, and other environmental stresses.

The Northeastern IPM Center has invested $1.5 million in projects related to improving our understanding of honey bee and pollinator health since 2003. The majority of this funding comes from the USDA National Institute for Food and Agriculture (NIFA). These studies add to the knowledge base that could help us protect honey bees, wild bees, and other insects and their $15 billion worth of pollination services. Pollinators help bring food to our table such as almonds, apples, oranges, sweet cherries, and blueberries. Those top five crops alone carry an annual value of nearly $8 billion in the United States.

Mystery deepens

At the recent Pollinator Health and Safety Conference held in South Portland, Maine, with representatives from the Northeastern IPM Center and its Pollinator Working Group attending, John Skinner of the University of Tennessee warned that scientists are seeing new symptoms distinct from classic colony collapse disorder that could indicate a new pathogen or problem.

Since the 1980s, bee colonies have been extensively damaged by a pest called the varroa mite. Varroa mites and small hive beetles could carry viruses and other pathogens into honey bee hives. Researchers are also concerned about tracheal mite, nosema, and other diseases. Interaction between fungicides and pesticides can make those pathogens more potent.

Skinner described the time he went to a beekeeper’s property to inspect his hives and to determine what was happening with bee die-off. They reached the last beehive. “The grower had used three different kinds of chemicals and a roach motel was in there, too. I said, ‘You’re a good beekeeper, but here’s what killed your bees. Off-label use of chemicals.’”

Multiple solutions

Nancy Ostiguy of Pennsylvania State University has been conducting research on bees for 16 years, and in 2003 received $142,255 from the Northeastern IPM Center to study lethal and sub-lethal effects of pesticides used to control varroa mite in honey bee colonies. At the Pollinator Health conference, she pointed out that pesticides have impacts beyond the target organism.

Dennis vanEngelsdorp, an entomologist at the University of Maryland, received a 2015 Partnership Grant from the Northeastern IPM Center. He plans to compare organic and conventional beekeeping practices, as well as study a technique called brood nest size restriction to control varroa mite.

Skinner, Ostiguy, and vanEngelsdorp (and many others) believe multiple factors are causing honey bee decline. The current approach to the problem, therefore, involves multiple avenues of research, hopefully leading to many new tools in the IPM toolbox.