On May 7, USDA released an annual survey, conducted by the Apiary Inspectors of America and the Bee Informed Partnership, showing that the mortality rate for honey bees in the United States over the previous seven months ending April 30 was more than twice what is considered sustainable.
The 31% mortality rate over the period was nine percentage points higher than the same period the previous year, confirming earlier anecdotal reports from the field that bee populations suffered severe losses last winter. Of the 6,000 commercial beekeepers responding in the survey, 70% reported losses above 14%, which is considered the economically sustainable threshold. The latest losses were the seventh consecutive winter during which mortality in honey bees was above either sustainability benchmark.
The survey did not pinpoint causes of the high mortality rate but did indicate some problem areas. For example, more colonies "dwindled away" in contrast to the sudden deaths associated with colony collapse disorder. This finding points to causes that include pesticides, parasites, disease and the shortage of forage resulting from widespread drought.
Another trend cited in this survey is that beekeepers who later took honey bees to California to pollinate almonds reported higher losses than beekeepers who did not take their bees to pollinate almonds. “Nearly 20% of the beekeepers who pollinated almonds lost 50% or more of their colonies," the survey found.
According to beekeepers and apiculturists in California, several contributing factors likely played roles. Many of the bees arriving in the almond grove were already weakened to the point that in previous years they would not have been rented. The weakened state of the bees was the result of an early spring that caught many beekeepers by surprise. Subsequently, many of the beekeepers fell behind in treating their hives for Varroa mites, a serious parasite of honey bees. There also was a lack of forage for the bees that require a balanced selection of pollen to maintain health.
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