What's causing colony collapse disorder (CCD)?

Are we any closer to determining the cause?

CCD, the mysterious malady characterized by bees abandoning the hive, leaving behind the brood and food storage, continues to be of great concern--and rightfully so.

The headlines today read:

• Scientists discover virus that could explain drop in bee population--Science News, Timesonline
• DNA clue to honey bee deaths--BBC

Which brings us to Extension Apiculturist Eric Mussen of the UC Davis Department of Entomology, the outgoing president of the Western Apicultural Society. He conducted the 31st annual conference, held last week in Healdsburg.

A noted expert on honey bees, Mussen is frequently asked "The CCD Question."

What does he think is causing CCD?

"As the pieces are coming together, I think that a still undetermined virus is causing the problem," Mussen says. "The malady appears to be 'contagious' and 'drying' the combs seems to reduce or eliminate it."

"Our bees need to be in top physiological condition. I believe that malnutrition puts a physiological stress on the bees, especially the immune and chemical detoxification systems. Then diseases and exposures to chemicals become very significant."

Beekeepers who do a lot of supplementary feeding, he says, see fewer problems.

So, if you're a beekeeper, place your hives in locations with an abundance of high quality pollens and nectar.

And don't ignore those combs.

"If a beekeeper has them on hand, the bees most likely would be better off on newer, less contaminated (with mite-killing compounds) combs," Mussen  says.

How can we help? We can plant trees, ornamentals, and flowers that provide food for the bees. "It's especially important to provide nectar and pollens at the end of the season--late summer and fall," he says. "That's when resources tend to become scarce."

What else can we do? Stop using pesticides on plants that bees visit. "The most suspect group of pesticides at this time are the neonicotinoid insecticides that move systemically in the plants," Mussen says. "They get into the nectar and pollen.  However, the fungicides, thought by many to be benign to honey bees, are pretty common contaminants and may be causing more problems than we think."

Meanwhile, the search for the cause(s) of CCD continues.

Bee well.