Tennessee bee population declines

Blount County beekeeper: "They were just gone"
Apr. 10, 2013 @ 11:50 AM

Since 2005, an international phenomenon known as colony collapse disorder has been killing off large numbers of bees that pollinate many crops grown for commercial use. Deaths have sharply risen over the past year.

Officials in Tennessee say the state’s beekeepers are also experiencing deaths in their colonies, but they might not have to do with CCD.

John Skinner, UT Extension specialist and professor in the Entomology and Plant Pathology Department, said CCD consists of a particular set of symptoms in a hive.

“We didn’t see that in Tennessee, but we still were losing colonies to something,” Skinner said.

Tennessee lost about a third of its bees last year, and several major factors are causing the decline, Skinner said. They include previously known causes for bee decline, like certain mites and bad beekeeping practices, but also emerging concerns, like new viruses.

“If you add one or the other of the potential maladies, that can cause a major effect,” Skinner said.

Local beekeeper Dennis Barry affirms that although CCD is an increasing factor in bee deaths, Barry said, what’s been afflicting local hives probably is not true CCD.

“What they’ve originally defined as CCD mostly was happening with migratory beekeepers, who have a few thousand colonies and move them around a lot (to pollinate different areas),” Barry said. “They were the ones really experiencing true CCD, but we’ve all had similar symptoms from time to time. It’s hard to define even.”

Barry keeps around 20 hives, from which he harvests honey to sell. He classifies himself as a sideliner, someone who doesn’t keep enough hives to be a professional beekeeper – but who still sells their product, unlike a hobbyist.

Like most beekeepers, he lost more bees last year, though not as many as some beekepers he knows. Barry, whose bee yard is in Blount County near Seymour, said the biggest sideliner in his area “lost quite a few hives this past winter.”

Like Skinner, Barry believes the bees’ deaths are caused by several different factors, including the parasitic Tracheal mites and Varroa mites, which can cause widespread decline in colonies.

Then there are the viruses of the nosema strain. A common bee virus is Nosema apis, but it’s not the only one.

“Now we have a new thing, a new strain of nosema called Nosema ceranae,” Barry said. “It’s an intestinal infection, and it’s pretty contagious.”

Barry said symptoms of N. ceranae don’t show up in a colony until it’s well infected. Beekeepers treat it by feeding bees sugar water with medication in it.

“Pesticides are also a concern,” Skinner said. “That has emerged to be a serious issue that we haven’t resolved yet.”

A new class of pesticides called neonicotinoids was introduced in 2005; bee populations have declined since then. The pesticides are systemic, incorporated into the seeds of the plant so that it carries the harmful chemical.

“The idea is the caterpillar eats the plant and then it kills the caterpillar,” Barry said. The problem is that bees take the same plant’s nectar and transport it back to the hive.

Barry said neonicotinoids, which have a chemical composition similar to nicotine, deal a sublethal dose and don’t kill bees directly. But they remain in the bees’ system much longer than older pesticides.

Barry believes that neonicotinoids likely contribute to CCD in other areas, but he maintains that the newer virus strain may be claiming more bees in East Tennessee.

“The bottom line is, this is just a small part of the bigger picture, which is bee decline,” Skinner said.

The decline is cause for serious concern.

Honey bees account for $14.6 billion in crops annually in the U.S., and $119 annually in Tennessee. Fewer bees may turn into higher food prices.

“(Bee decline) is severe for honey bees because they pollinate commercial crops and many other things,” Skinner said.

The phenomenon has been devastating to hobbyists and sideliners, too. Barry described what it was like when the increases began.

“When it first started, you’d just come out and there would be no bees left,” he said. “They were just gone.”