During spring and summer, four of 10 honeybee colonies will be under stress from Varroa mites, beekeepers said in the first issue of USDA’s Honey Bee Colonies report. By far, the parasitic insects are a greater problem than other pests, diseases, pesticides, bad weather and poor nutrition, according to the survey of beekeepers.
When other pests and parasites are counted in addition to the Varroa mite, 60 percent of colonies are affected by the vectors during the busy warm-weather months. Pesticides affected approximately 16 percent of colonies during spring and summer, disease 7 percent, and factors such as bad weather and poor nutrition, 10 percent.
There were 2.59 million honeybee colonies in the country at the start of 2016, down 8 percent from 2.82 million on Jan. 1, 2015. Colony totals were lowest in winter and highest during the summer. The peak was 3.13 million on Oct. 1, at the end of summer.
Keepers constantly add and renovate colonies to offset losses that usually are worst during winter, around 18 percent of colonies, according to the USDA report.
Summer loss rates have rivaled the winter rates since 2014, said the Bee Informed Partnership, a research coalition, on Tuesday. Summer losses are worrisome because bees should be their healthiest then. Keepers lost 44 percent of honeybee colonies in the year ending in April, said Bee Informed. USDA did not estimate annual losses.
“About one mouthful in three in our diet directly or indirectly benefits from honeybee pollination,” says USDA’s Agricultural Research Service. “Commercial production of many high-value and specialty crops like almonds and other tree nuts, berries, fruits and vegetables depend on pollination by honey bees.”