Scientists Blame Pesticides for Honeybee Decline

New colony collapse disorder research finds dozens of pesticides in honeybees and their hives.

March 22, 2010

Agricultural chemicals are wiping out bees that pollinate our crops and flowers.

RODALE NEWS, EMMAUS, PA—Bee fan or not, we all rely on the insects to pollinate the fruit, nut, and vegetable crops we enjoy every day. But in the last few years, the populations of our pollinators, particularly honeybees, have been plummeting. Dubbed colony collapse disorder, the cause of the devastation isn't known. There are many theories, from mites and viruses to cellphone towers. One potential cause—pesticides—gained more credibility this week with the release of a new study by Pennsylvania State University. Researchers found "unprecedented levels" of pesticides in honeybees and hives in the United States.


THE DETAILS: Scientists tested wax, trapped pollen, and honeybee specimens for chemical pesticides and chemicals originating from those pesticides. Investigating pesticide residue in samples taken from beekeepers from 23 states and one Canadian province during the 2007 to 2008 growing season, researchers found 121 different pesticides and metabolites in the 887 wax, pollen, bee, and hive samples. Nearly 60 percent of the 259 wax and 350 pollen samples contained at least one systemic pesticide—a type of poison that doesn't remain on the surface of plants, but is taken up inside the plant, too, where honeybees go to feed. Here are just a few of the chemicals they uncovered:

• Coumaphos—An insecticide used to control livestock pests, such as flies, lice, scabies, and ticks. It interferes with proper functioning of the nervous system of both humans and insects and is also highly toxic to birds. This type of pesticide falls into the organophosphates category, a class of pesticides that has been linked to the most common type of childhood cancer.

• Carbaryl—A wide-spectrum insecticide designed to kill insects on citrus, other fruit, and cotton, and on trees and in lawns.

Read on to find out other harmful chemicals that have been found in hives.

• Chlorothalonil—A popular fungicide used on a wide variety of crops that other studies have implicated in colony collapse disorder. The Environmental Protection Agency lists it as a potential human carcinogen.

• Fluvalinate—Used to control mites in bees, this pyrethroid chemical turned up in nearly all honeycomb and foundation wax samples because commercial beekeepers use it to avoid devastating mite infestations that can wipe out colonies. "Potential for interactions among multiple pyrethroids and fungicides seems highly likely to impact bee health in ways yet to be determined," the study authors write.

Atrazine—A pesticide that also contaminates human drinking water, and one that a recent study found actually castrates male frogs. While it is not directly considered toxic to bees, it's unclear how it affects organisms when it mixes with other pesticides that are common in the environment.

WHAT IT MEANS: It appears some of these chemicals are (at least partially) responsible for the annihilation of honeybees. And they're certainly not good for us, either. As Rodale Inc. CEO Maria Rodale points out in her new book, Organic Manifesto, farming chemicals are linked to all sorts of human ailments, including some cancers, diabetes, ADHD, autism, and more.

To help protect the health of your family (and the honeybees'), join the Demand Organic campaign. To learn more about why organic matters (and how to buy it on the cheap), read How to Protect Yourself from 7 Food-System Threats. To learn more about managing your own yard without using questionable chemicals that could hurt your family and beneficial critters, read 7 Chemical-Free Fixes for Common Lawn Problems.