Bee colonies collapsing and implications for gardeners and homeowners

Editor’s note: This article is from the archives of the MSU Crop Advisory Team Alerts. Check the label of any pesticide referenced to ensure your use is included.

If you have been listening to the radio or reading papers the last few weeks, chances are you have already heard about the alarming honey bee die-offs around the country. The phenomenon is officially named “colony collapse disorder” (CCD). This disorder has the media all excited because it is large in scale (25 states are affected), came in quick (colonies that were fine in August/September collapsed around October/November), and hit people hard (many beekeepers with hundreds to thousands of colonies are losing 50-90 percent of their colonies). The worst of all of these scenarios; we do not yet know what causes it.

The symptom seems to be that bees simply disappear, which is why peopled initially called it the disappearing disease (or fall dwindle disease). A colony with 40,000 bees in the fall, apparently healthy with lots of honey and pollen, suddenly has nothing or a handful of bees with a queen left. Very few dead bees are found inside the hive or near the entrance. Strangely, wax moths, small hive beetles are slow in moving into such newly abandoned colonies. Several possible causes come to mind. When tracheal mites (Acarapis woodi) first showed up in North American (circa 1983), we had bees disappearing also. The disappearing mostly happened during the over-wintering process – colonies had small clusters or no bees in the spring because bees with their trachea plugged with mites could not make it back to the colony after defecation flights or they simply flew out to die in the late fall.

A new species of nosema (Nosema ceranae, so named because it was discovered first in the Asian honey bees, Apis cerana) also showed up in the European bees (Apis mellifera, the only species we have in North America and Europe) in Europe during the summer of 2006 and killed up to 60 percent of bees in some apiaries. Recently, it was confirmed to be present here in our bees in the United States.

Another concern is all the chemicals we have been throwing into the bee colonies, which conceivably can weaken the immune system of honey bees or affect their learning and orientation. A few years ago, French beekeepers suspected that “mad bee disease,” where bees got confused and could not return home successfully, was related to the use of an insecticide called Gaucho.

Unfortunately, all these factors (tracheal mites, nosema disease and pesticide use) have been all ruled out for being the cause of CCD. Scientists from Montana State University, North Carolina State University, Penn State University and USDA Beltsville Bee Lab have been collecting and analyzing a large number of bee samples. Hopefully, we will have the answer soon.

While the number floating on the Internet has put the colonies affected by CCD to be around 600,000 colonies nationally, which is about a quarter of the total colonies in the country, gardeners and homeowners in Michigan will not notice a big difference in honey bee presence on garden and wild flowers. While Michigan is certainly on the map as a state being affected with CCD, it is not clear how many beekeepers are affected in Michigan. Even when we have a large winter die-off, most beekeepers replenish their bees around now (April) with package bees from the south. There were rumors that some package bee producers are affected by CCD, so it is possible that beekeepers and growers will be impacted, but I do not anticipate a big impact to most gardeners and homeowners.

Get more bee information from Dr. Huang’s web site at: http://bees.msu.edu/

Dr. Huang’s work is funded in part by MSU‘s AgBioResearch.

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