Honey bees climb across a honeycomb covered with almond flower pollen. (Photo by Lynn Ketchum)
CORVALLIS, Ore. – As the worldwide population of honey bees continues to decline, the Oregon State University Extension Service and partners have updated a tool for Pacific Northwest growers and beekeepers to reduce the impacts of pesticides on bees.
The revision of OSU Extension’s publication appears after an estimated 50,000 bumble bees died in a Wilsonville parking lot in June. The Oregon Department of Agriculture confirmed in a June 21 statement that the bee deaths were directly related to a pesticide application on linden trees conducted to control aphids. The episode prompted the ODA to issue a six-month restriction on 18 insecticides containing the active ingredient dinotefuran.
OSU researchers are investigating the effects of broad-spectrum neonicotinoids, such as dinotefuran, on native bees. The work is in progress, according to Ramesh Sagili, an OSU honeybee specialist.
The newly revised publication “How to Reduce Bee Poisoning from Pesticides” includes the latest research and regulations. Lead authors include Sagili and OSU toxicologist Louisa Hooven. Download the updated version for free online at How to Reduce Bee Poisoning form Pesticides (pdf).
“More than 60,000 honey bee colonies pollinate about 50 different crops in Oregon, including blueberries, cherries, pear, apple, clover, meadowfoam and carrot seed,” Sagili said. “Without honey bees, you lose an industry worth nearly $500 million from sales of the crops they commercially pollinate.”
Nationally, honey bees pollinated about $11.68 billion worth of crops in 2009, according to a 2010 study on the economic value of insect pollinators by Cornell University.
Growers, commercial beekeepers and pesticide applicators in Oregon, Washington, Idaho and California will find the publication useful, Sagili said. An expanded color-coded chart details active ingredients and trade names of more than 100 conventional and organic pesticides, including toxicity levels to bees and precautions for use.
The publication also describes residual toxicity periods for several pesticides that remain effective for extended periods after they are applied. Additionally, the guide explains how to investigate and report suspected bee poisonings.
Nationwide, honey bee colonies have been declining in recent years due to several factors, including mites, viruses transmitted by mites, malnutrition and improper use of pesticides, Sagili said. In Oregon, about 22 percent of commercial honey bee colonies were lost during the winter of 2012-13, Sagili said. There has been a gradual, sustained decline of managed honey bees since the peak of 5.9 million colonies in 1947, according to the Cornell study. The number of managed colonies reached a low of 2.3 million in 2008, although there were increases in 2009 and 2010, the study said.
“Growers and beekeepers can work together with this practical document in hand,” Sagili said of OSU Extension’s publication. “It gives them informative choices.”
For example, when commercial beekeeper Harry Vanderpool needed to advise a pear grower on whether an insecticide was acceptable to use around bees, he turned to OSU Extension’s publication.
“That manual has been a blessing,” said Vanderpool, who keeps 400 hives in South Salem to pollinate dozens of crops for growers from California to central Oregon. “It’s a tool that helps beekeepers and farmers work together in the right way with the right chemical rather than us telling farmers how to farm or farmers telling beekeepers how to keep bees.”
You can also find OSU’s publication by searching for PNW 591-E in OSU Extension’s catalog at http://extension.oregonstate.edu/catalog. The publication was produced in cooperation with OSU, Washington State University and the University of Idaho.