[permaculture] Asian Parasite Killing Western Bees - Scientist

Lawrence F. London, Jr. lflj at bellsouth.net
Thu Jul 19 10:17:47 EDT 2007

Asian Parasite Killing Western Bees - Scientist
SPAIN: July  19, 2007

MADRID - A parasite common in Asian bees has spread to Europe  and the
Americas and is behind the mass disappearance of honeybees in many  countries, says
a Spanish scientist who has been studying the phenomenon for  years.

The culprit is a microscopic parasite called nosema ceranae said  Mariano
Higes, who leads a team of researchers at a government-funded apiculture  centre
in Guadalajara, the province east of Madrid that is the heartland of  Spain's
honey industry.

He and his colleagues have analysed thousands of samples from stricken  hives
in many countries.
"We started in 2000 with the hypothesis that it was  pesticides, but soon
ruled it out," he told Reuters in an interview on  Wednesday.

Pesticide traces were present only in a tiny proportion of samples and  bee
colonies were also dying in areas many miles from cultivated land, he said.

They then ruled out the varroa mite, which is easy to see and which was  not
present in most of the affected hives.

For a long time Higes and his colleagues thought a parasite called  nosema
apis, common in wet weather, was killing the bees.

"We saw the spores, but the symptoms were very different and it was
happening in dry weather too."
Then he decided to sequence the parasite's  DNA and discovered it was an
Asian variant, nosema ceranae. Asian honeybees are  less vulnerable to it, but it
can kill European bees in a matter of days in  laboratory conditions.

"Nosema ceranae is far more dangerous and lives in heat and cold. A  hive can
become infected in two months and the whole colony can collapse in six  to 18
months," said Higes, whose team has published a number of papers on the

"We've no doubt at all it's nosema ceranae and we think 50 percent of
Spanish hives are infected," he said.
Spain, with 2.3 million hives, is home  to a quarter of the European Union's

His team have also identified this parasite in bees from Austria,  Slovenia
and other parts of Eastern Europe and assume it has invaded from Asia  over a
number of years.

Now it seems to have crossed the Atlantic and is present in Canada and
Argentina, he said. The Spanish researchers have not tested samples from the
United States, where bees have also gone missing.

Treatment for nosema ceranae is effective and cheap -- 1 euro (US$1.4)  a
hive twice a year -- but beekeepers first have to be convinced the parasite is
the problem.

Another theory points a finger at mobile phone aerials, but Higes notes  bees
use the angle of the sun to navigate and not electromagnetic frequencies.

Other elements, such as drought or misapplied treatments, may play a  part in
lowering bees' resistance, but Higes is convinced the Asian parasite is  the
chief assassin.

Story by Julia  Hayley

More information about the permaculture mailing list