Colony collapse research efforts realizing results
By Kathy Barnard, Marketing and News Services
Pesticide residue in old honeycomb and a new microscopic pathogen quietly spreading throughout the United States are two big contributors to the mysterious Colony Collapse Disorder that has wiped out thousands of hives throughout the Pacific Northwest over the past several years, according to recent research results from WSU scientists.
Working on the project funded in part by regional beekeepers and WSU’s Agricultural Research Center, entomology Professor Walter (Steve) Sheppard and his team have narrowed the list of CCD culprits.
Research indicates that pesticide residue in old honeycomb has had an adverse effect on bee populations. |
“One of the first things we looked at was the pesticide levels in the wax of older honeycomb,” he said. Using combs contributed by U.S. Department of Agriculture, Sheppard found “fairly high levels of pesticide residue.” Bees raised in those hives “had significantly reduced longevity,” he said.
One easy solution is for beekeepers to change honeycombs more often. In Europe, for example, apiarists change combs every three years. “In the U.S., we haven’t emphasized this practice and there’s no real consensus about how often beekeepers should make the change. Now we know that it needs to be more often,” Sheppard said.
Another aspect of Sheppard’s work—with graduate student Matthew Smart—focuses on a microsporidian pathogen known as Nosema ceranae, which attacks the bee’s ability to process food. Beekeepers have considered it to be “the smoking gun” behind colony collapse.
“Nosema ceranae was only recently described in the U.S., the first time in 2007,” Sheppard said. “But while no one really noticed, it has spread throughout the country.”
Sheppard’s earlier research found it to be a tough bug to battle. Of 24 hives checked in early 2008, Nosema build-up was high in a majority of the bees sampled. Beekeeper Eric Olson of Yakima said he treated the hive with a mega-dose of the antibiotic fumagillin. “That should have caused the Nosema to either disappear or at least go down, but the levels went up,” he said.
The next step, Sheppard added, is to look at the link between Nosema ceranae and verroa mites, a common pest for honeybees.
Breeding bees resistant to Nosema ceranae and other pathogens is another battle front, he added. “All of this information informs our long-term breeding program.”
Sheppard said that while he and his team are making progress on finding the causes of colony collapse, beekeepers continue to lose a higher-than-normal percentage of their hives.
“The beekeepers I’ve spoken with are estimating a 30 percent winter loss this past year,” he said. “That’s a little bit lower than the year before, but still higher than one would expect.”
The Washington State Beekeepers Association estimates statewide losses to the disease at between 35 and 50 percent in recent years. With eight out of 10 of Washington’s most valuable crops—including apples—being “bee dependent,” Colony Collapse Disorder, left unchecked, could jeopardize the state’s agricultural economy.