January 27, 2014

Plant virus linked to bee colony collapse

bee colonyOur early spring like weather may mean fruit trees will benefit from better bee activity. When temperatures are cold bees are less likely to be out pollinating early blooming fruit and nut trees like almonds and apricots. This year if our warm spell continues there should be plenty of bees available to pollinate early bloomers.

Sonoma County agriculture and our entire state are dependent on bees to keep our farms, fields and orchards pollinated and producing. Thousands of bees are transported to the Central Valley each year to pollinate almond trees. There are currently 800,000 acres of almonds in production in California and almonds are a $3 billion industry in our state. In Sonoma County we have over 60,000 acres of vineyards producing around $500 million in grape production.

Maintaining a healthy bee population is the goal of researchers who are working to identify reasons for bee colony collapse. A routine inspection by the U.S. Department of Agriculture found tobacco ring spot virus on commercial honeybees that are used for pollination. The L.A. Times reports that tests show this RNA virus was replicating inside the bees and spreading from bee to bee in the colony through mites.

The tobacco ringspot virus “acts as a quasi specie, replicating in a way that creates ample mutations that subvert the host’s immune responses” according to the Times.
Judy Chen, a researcher for the USDA laboratory in Maryland states: “The cause of colony collapse remains unclear. But we do have evidence that TRSV along with other viruses that we screen on a regular basis are associated with lower rates of over winter survival.”

Other viruses, pesticides and fungicides have also been linked to bee colony collapse. Scientists from the USDA and EPA have found that pesticides, pathogens and nutritional deficits, some caused by a shortage of natural forage, were the major contributing factors behind colony collapse disorder said the L.A. Times.

Bees are often fed high fructose corn syrup to provide food for the colony through the winter months but bees which survive on their own honey, were less susceptible to microbial pathogens and the effects of pesticides.

In our own home gardens and orchards we can reduce the use of fungicides and pesticides that are harmful to bees. There are several over the counter products that have chemicals which are highly toxic to bees. There are hundreds of products available for home use that share active ingredients that should be avoided for the health of bees in your home garden. Here is a list of pesticides highly toxic to bees: carbaryl, carbamates, organophosphates, pyrethroids, chlorinated cyclodiene and imidicloprid. Read the label and look for these active ingredients prior to using products where bees are present.

To help provide food for wild bees consider planting some of the foraging plants suitable for planting in Sonoma County. Visit the Sonoma Bee Keepers Association website at www.Sonomabees.org. Look for the “Plant 4 bees” download handout for a list of bee friendly plants.

For more information on reducing toxic in your home landscape visit our website at treeprosonoma.com and click on the articles tab. Choose the “Home and Property Tree Safety” tab to locate the article “Reducing Toxins in Your Home Landscape”.