Sunday, May 15, 2011

Four Years of CCD

We are four years into the greatest recorded die-off of honey bees. Since the spring of 2007, beekeepers across North America have experienced colony losses averaging 30 percent each year, typically over the winter. Studies of the causes of the losses, known as Colony Collapse Disorder, have been made and continue. Much more is now known about the factors affecting honey bee health. However, a single source of the condition which results in the loss of a hive’s adult population has not been identified. It seems that multiple conditions exist when colonies collapse. The first common element identified with the honey bee die-off is colony stress. Bees may be under stress from confinement due to transportation for pollination service or from nutritional deficiencies caused by weather, lack of bee plants in monoculture agriculture, or from exposure to insecticides and chemical toxins in the environment. Initial reports of the causes of Colony Collapse Disorder identify honey bee viruses, often vectored by parasitic Varroa mites, and a new strain of Nosema disease, Nosema ceranae. Still unanswered is the effect on honey bees of the use in the environment of neonicotinoids, systemic insecticides brought back to the hive by bees foraging for nectar and pollen. Of special concern are imidacloprid and clothianidin. Their safety is strongly questioned by beekeepers. Study, independent of the chemical manufacturers, is needed to assure their safety.

Colony Collapse Disorder has changed beekeeping over the past four years. The public has become acutely aware of the honey bee’s role in producing our food. Beekeepers have adjusted their management practices to control bee diseases and keep colonies healthy. There has been a shift from the use of harsh chemicals for parasitic mite control to less stressful or chemical-free measures. The importation of honey bees into the United States, allowed in 2006, is again blocked. Breeding bees resistant to the effects of parasitic mites is increasingly the promise for healthier honey bees. Today’s photo: foraging pollen from native Arkansas dogwood trees.

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