AMHERST, Mass. - The mysterious disappearance of honeybee colonies in the United States due to colony collapse disorder is a major concern for New England growers of cranberries and blueberries, who must rent thousands of hives from commercial bee operations to maintain fruit harvests worth over $100 million each year.

John Burand of the University of Massachusetts Amherst has received a three-year, $150,000 grant from the U.S. Department of Agriculture for research aimed at improving the health of honeybees and bumblebees, which are the main pollinators of blueberries and cranberries and important pollinators of apples, squash and pumpkins.

Collaborators on the grant include Anne Averill and Stephen Rich of the UMass Amherst department of plant, soil and insect sciences, who formed the UMass Amherst Bee Consortium with Burand in the fall of 2007, and Francis Drummond, an insect ecologist from the University of Maine at Orono.

Since 2006, the workers in many honey bee colonies in the United States have vanished due to colony collapse disorder (CCD), a condition where adult worker bees abandon a seemingly healthy hive. Averill, an insect behaviorist and team leader at the UMass Amherst Cranberry Station, has also noticed that some species of bumble bees are disappearing.

"We don't know the cause of CCD or the reasons behind the disappearance of certain bumblebees, but the working hypothesis is that a number of factors are stressing bees, including diseases, parasites and pesticide use," says Burand, an insect pathologist.

Burand and his colleagues will approach the problem from a unique angle, analyzing bees donated by local and commercial beekeepers to determine the types of microbes they carry. "One wild hive of honeybees in good health will also be sampled," says Burand, who is in the process of identifying beekeepers that will contribute bees to the study.

Genetic material from the samples will be sequenced in the laboratory of Stephen Rich, a medical entomologist who specializes in diseases carried by insects such as Lyme disease and malaria, allowing the team to identify which microbes are present in each colony, including bacteria, fungi and a host of bee viruses, and how many of each type are present.

"Some of these microbes cause disease in bees, but others are considered beneficial, and to make things more complicated, disease organisms are usually present in perfectly healthy hives," says Burand. "We may find that a balance between harmful and beneficial microbes is necessary to keep diseases in check and maintain a healthy hive, and that environmental factors like pesticide use are altering this balance."

The microbes from thriving bee colonies will be compared to colonies that are not doing as well, which may lead to the development of a microbial indicator test for bee colony health. The ultimate goal of the research is to develop efficient methods of monitoring the viruses, bacteria, fungi and other microbes carried by both native and commercially managed bumblebee and honeybee populations in the northeastern United States.

Bee colonies will also be exposed to insecticides to assess the effect of each treatment on the microbes present in the colonies, and a correlation between changes in microbial populations and bee health will be noted. Beekeepers will also be surveyed about the kinds of treatments used in their hives, including antibiotics and fungicides.

"This information will provide a better understanding of factors affecting bee health, and hopefully lead to pest management practices that will contribute to the health of bees," says Burand.

The grant was received from the U.S.D.A. Northeast Regional Integrated Pest Management Competitive Grants Program.