Those Dratted Mites

Nov 25, 2008

Those dratted mites.

UC Davis entomologist Robbin Thorp, emeritus professor and a native bee pollinator specialist, sent us a BBC report linking a varroa mite infestation to a devastating honey production loss in the UK. It's the worst honey crisis ever to hit the UK.

In short: beekeepers are concerned that by Christmas, there may be no more domestically produced honey left on the supermarket shelves.

The mite infestation has already killed off an estimated quarter of the UK's honey bees, according to BBC correspondent Jeremy Cooke, who said about "one in three colonies has been wiped out."

The varroa mite, or the Varroa destructor, is a nasty pest. Now found in most countries (Australia is an exception), it's an external parasite initially discovered on the Asian honey bee, Apis cerana. Over the last few decades, however, it has spread to the Western honey bee (also known as the European honey bee), Apis mellifera.

The varroa mite entered the UK in 1992, reports show. It has since spread throughout England, Wales, Scotland and Northern Ireland.

The blood-sucking parasite feeds on both adults and the brood (immature larvae). It weakens the bees, opening them up to all sorts of diseases. And eventually, if not controlled, it will destroy the colonies.

The bad news is that the varroa mite cannot be completely eradicated, but with proper control methods, the mite population can be kept at a low level.

When California State Secretary of Agriculture A. G. Kawamura visited the Harry H. Laidlaw Jr. Honey Bee Research Facility at UC Davis last month, bee breeder-geneticist Susan Cobey showed him dead mites  on a hive floor. (See story on UC Davis Department of Entomology site.)

Kawamura is no stranger to bees or bee pests. As a youth, he reared bees--until the infectious bee disease, American foulbrood, upset his plans.

To control the mite, beekeepers usually use a combination of management methods. They use biotechnical methods and chemical controls. Unfortunately, in some areas, the varroa mite is developing resistance to miticides--another worry for beekeepers.

Said Cobey: "You need to reduce mite levels in colonies  by late summer--August/September--to have healthy bees in spring."

"This is getting increasingly  difficult  as the mites have developed resistance to  most  of the (hard) chemical  miticides used, such as Fluvalinate  and Coumaphos and Amitraz."
 
It's important to have resistant bee stock, she said. "Put the selection pressure in the wrong place--on the mites, not the bees!"

Cooperative Extension apiculturist Eric Mussen of UC Davis says that in California, the Department of Pesticide Regulation "is close to approving another chemical treatment" to help control the mite problem.

It may be ready by next spring.

The mites will be waiting.

 

 

 


By Kathy Keatley Garvey
Author - Communications specialist

Attached Images:

A varroa mite (see reddish-brown spot on bee's thorax) at the Harry H. Laidlaw Jr. Honey Bee Research Facility, UC Davis. Varroa mites are native to Asia. (Photo by Kathy Keatley Garvey)

Mite on Drone

MITES ON HIVE FLOOR--UC Davis bee breeder-geneticist Susan Cobey points to two varroa mites on a hive floor. The varroa mite is an external parasite of honey bees.(Photo by Kathy Keatley Garvey)

Mites on Hive Floor