Bees, beekeepers and big growers

To track these issues and provide an accurate picture of the health of the nation’s bees, USDA/APHIS initiated the USDA Honey Bee Pests and Diseases Survey Project. The project is a comprehensive study aimed at documenting which bee diseases, parasites and pests are present (or likely absent) in the U.S. The survey will focus on verifying the absence of the Asian honeybee (Apis cerana), Slow Paralysis Virus (SPV) and the parasitic mite Tropilaelaps.


Apiarist Craig Cella searches for the queen among the workers.
PHOTO BY SALLY COLBY.

International trade law prevents the U.S. from banning imports of bees from other nations unless the exporting nation has a disease, parasite or pest of bees that is not currently present in the U.S. This means that we must prove that specific pests and diseases are not present in any area of the U.S.

“Tropilaelaps, an Asian parasitic mite, is what triggered the whole project,” said Karen Roccasecca, who heads the Apiary Registration Program in Pennsylvania. “We can’t ban the import of bees from other countries unless we can prove that they have a pest that we don’t have.” Roccasecca explains that like Varroa, Tropilaelaps attacks the brood, but Tropilaelaps breeds faster. “They’re smaller, and if you don’t know exactly what you’re looking for, they can be missed.”

The natural host of Tropilaelaps is Apis dorsata, the giant Asian honeybee. Other Asian honeybee species are infested, and there is evidence that the Western honeybee may also be infested. Tropilaelaps is reddish brown, about 1 mm long and .6 mm wide, moves freely and quickly on combs and feeds on brood. The resulting damage is similar to that of Varroa, but Tropilaelaps reproduces more rapidly and has a shorter life cycle. Adult Tropilaelaps lay eggs on mature bee larvae 48 hours after capping, and eggs hatch within about 12 hours and begin to feed on the developing bee. Adult mites enter cells with larvae and reproduce within the sealed brood. Affected bees may have stunted growth and deformed wings. Tropilaelaps can lead to bees absconding from the hive, adult bees with a shortened life span, and colony decline and collapse. Researchers predict that if both Varroa and Tropilaelaps were present in a colony, the population of Tropilaelaps would increase far more rapidly.


Entomologist Jeff Pettis examines a screen that separates live Varroa mites from bees. Results from the USDA Honey Bee Pests and Diseases Project will determine Varroa mite levels in colonies, which will help beekeepers establish controls.
PHOTO BY PEGGY GREB.

Although Tropilaelaps is native to climates that differ from most of the U.S., scientists aren’t sure what areas will support the species. “Even if it doesn’t survive winter, it will come in with new packages,” said Roccasecca. “We’d still have to deal with it during the season.”

The national survey was initiated in 2009 as a test study in Florida, California and Hawaii. In 2010, 13 states joined the effort, and 35 states are enrolled for 2011 and into 2012. The survey involves a comprehensive examination and sampling of bees from 25 apiaries in each participating state (except California, where 50 apiaries will be sampled). Collected bees are submitted to the USDA/ARS Bee Research Laboratory in Beltsville, Md., for study. The collector will conduct a visual inspection of hives and check for evidence of American foulbrood, European foulbrood, deformed wing virus, black shiny bees, chalkbrood, sacbrood, parasitic mite syndrome (PMS/snotty brood), small hive beetle adults and larvae, and wax moth adults and larvae. Laboratory analysis of preserved bee samples will include Nosema spore count, tracheal mite loads, Varroa loads and the presence of Tropilaelaps. Molecular analysis will include testing for the presence of Apis cerana, acute bee paralysis virus, deformed wing virus, Israeli acute paralysis virus, slow paralysis virus, Nosema ceranae and Nosema apis.

Data from the national survey will be used in the USDA’s CCD Action Plan. In addition, results from the survey will be combined with information collected by Bee Informed (www.beeinformed.org), a national extension effort to determine overall management practices of apiaries.

“Surveys done over five consecutive years showed a greater than 30 percent winter loss nationwide,” said Karen Rennich, project manager for both the national survey and the Bee Informed partnership. “It’s a problem in that beekeepers have to replace those hives in the spring.” Rennich added that although winter losses are relatively easy to make up, it would be far easier for beekeepers if they didn’t have to deal with annual winter loss.

“We sent out the first surveys in April 2011 to look at the management practices of beekeepers all across the country,” said Rennich. “These include migratory beekeepers, stationary beekeepers, large commercial beekeepers [and] backyard hobbyist beekeepers. Do they treat for Varroa? Do they treat for Nosema? Do they feed bees, and if so, what do they feed them?”


Apiarist Craig Cella inspects a frame for signs of disease.
PHOTO BY SALLY COLBY.

Rennich explained that the information on practices and problems throughout the country will be entered in a database. The project will identify management practices that keep colonies alive rather than looking only for factors that increase the risk of mortality. Once there is sufficient data from all areas of the country, beekeepers will be able to log in with their location and learn about the problems in their area and how other beekeepers are dealing with those problems.

“All the past disease data from the APHIS survey will be in the database,” said Rennich. “For example, people will be able to find out the typical regional load for Nosema spores. They’ll also be able to find out what management practices are best for their area – what works in the Southwest won’t work for beekeepers up in Maine.” In addition, 20 years of disease data from the Beltsville Bee Lab will be added to the database. “We’ll have historic as well as current data,” said Rennich. “We’re also hoping to have data from apiary inspectors throughout the country.”

The first winter loss survey includes data from 5,300 participants and apiary management data from 3,500 participants. Results will be released within the next few months and will be available on the Bee Informed website. “We hope that as these results are released, more people will take the survey next April,” said Rennich, adding that the database will be linked from the Bee Informed site, and will be interactive so beekeepers can access the data they need.


An adult female Varroa mite feeds on a developing bee. Researchers predict that if the Asian parasitic mite Tropilaelaps becomes established in the U.S., damage to colonies will be far worse than with Varroa alone.
USDA PHOTO BY SCOTT BAUER

So, what do beekeepers gain from these studies? An extensive database of information from nationwide apiary surveys combined with historical and regional data that will provide specific information about a variety of diseases and pests of honeybees. It’s a win-win for the bees, the crops they pollinate, and for those dedicated to preserving the art and science of beekeeping.

The author is a frequent contributor and freelance writer who farms and raises Great Pyrenees in south-central Pennsylvania. Comment or question? Visit www.farmingforumsite.com and join in the discussions.