A beehive placed on an Ashe County Christmas tree farm last June to monitor the effects of pesticides on honey bees was healthy and active when opened April 5, offering a living rebuttal to critics who link tree farms to a recent rash of “hive kills” in the region.
“Christmas trees get villainized a lot,” said N.C. State Cooperative Extension Agent Travis Birdsell. “I think it’s an image problem, when you drive by and see somebody in a (hazmat suit) spraying.”
On April 2, the Jefferson Post ran a story in which local beekeepers suggested use of pesticides on tree farms might be responsible for unprecedented bee losses.
But, while other beekeepers in the area reported losses of 50 percent or more since last fall, N.C. State Cooperative Extension Forestry Specialist Dr. Jill Sidebottom found her Omni Farm test hive robust enough to split into two hives.
According to beekeepers, the latest hive kill epidemic is symptomatic of colony collapse disorder, the mass dying-off of honey bees that hit the U.S. in 2006.
While the exact cause or causes of CCD are not known, beekeepers nationwide are looking at pesticides as a prime suspect. In March, beekeepers sued the Environmental Protection Agency for approving registration of pesticides they claim harm honey bees and other pollinators.
Sidebottom’s experimental hive is part of her research in integrated pest management on tree farms. Surrounded by 180 acres of trees managed with pesticides, the bees have fared well, she said.
The test hive was sealed only when treating the five-acre stand of Fraser firs nearest the bees, to spare them direct, concentrated doses of pesticides, she said. A control hive, set up in Wilkes County, did not survive the winter.
In addition to the test hive, Sidebottom has also studied populations of honey bees and other pollinating insects at tree farms in Ashe, Alleghany, Avery, Watauga and Mitchell counties. Using a large catch net, she sampled flying insect populations in six tree fields and found a diverse cross-section of pollinators including honey bees, bumblebees, mining bees, large and small carpenter bees, sweat bees, yellow-faced bees, digger bees, butterflies and others.
“The take-home message is Christmas trees are great habitat for pollinators,” Sidebottom said.
According to Birdsell, this is due to evolving practices in tree farm management.
In recent years, tree farmers have increasingly adopted cultivation of flowering ground-cover — like clover, flowering mustard and purple deadnettle — to control tall grass and weeds around trees as an alternative to herbicides, said Birdsell. Ground cover also keeps the soil cooler and fixes nitrogen to tree roots.
Ninety-five percent of tree farmers have implemented this practice, with the result that tree growers are using fewer chemicals, he said.
“We’ve worked very hard, the whole industry has, to work with the bees,” said Birdsell. “We have more pollinators in this area than anywhere else in the state.”
“The average tree farm only gets sprayed 1.3 times per year,” Birdsell said.
The problem comes when a grower does need to treat for an insect or mite pest when bees are present, said Sidebottom. Bees are most at risk when pesticides are applied during the day while ground-cover is flowering.
When certain types of pests require daytime spraying, growers should first apply a reduced concretion of herbicide to burn back flowers without killing the ground cover, she said. Honey bees and other pollinators will then not be drawn to forage when pesticides are applied.
While most insecticides used on Christmas trees are toxic to bees, neonicotinoids — strongly implicated in the CCD debate — are not widely used in the tree industry, Sidebottom said, although some growers have used “neonics” to control elongate hemlock scale, an insect pest afflicting hemlock trees.
In Ashe, the third largest Christmas tree producing county in the nation, Birdsell suggests open lines of communication between tree growers and beekeepers: “If you’re having a problem, if you know you have a Christmas tree grower near you, let them know you have bees.”