Research Links Bee Deaths to Neonicotinoid Pesticides
A new study by researchers from Purdue University has confirmed the link between mass honeybee die offs (also called colony collapse disorder) and pesticides – especially systemic neonicotinoid pesticides.
The researchers investigated a rash of mass beehive deaths among bees in Indiana during the spring of 2010 and 2011. They analyzed the bodies of dead bees, along with the hives that were abandoned during the die-offs. The researchers also set up test fields with and without pesticides surrounded by hives to confirm the cause of the disappearing and dying bees.
The analyses revealed the dead bees, hives of the dead and missing bees and the pollen collected by the dead bees prior to their deaths contained significant amounts of neonicotinoid pesticides clothianidin and thiamethoxam.
Meanwhile, their analyses of other healthy hives found that these pesticides were not present in the healthy hives, the healthy bees or their collected pollen.
As opposed to the spraying of pesticides, neonicotinoid pesticides are typically applied to plant seeds before they are planted. This coating makes pesticides systemic within the growing plant, and appear in the pollen of the plant. One of the biggest sources of these neonicotinoid-pesticide seeds is Bt corn, supplied by Monsanto.
The planting of BT corn has grown significantly in the United States over the past few years – the same period the massive bee deaths of colony collapse have occurred. The 2010 corn plantings in the U.S. was the highest on record, with 88 million acres planted. 2011 was projected to be even higher.
Practically all of the corn planted within the U.S., with the exception of organic corn, is being planted using seeds coated with neonicotinoid pesticides. Organic corn plantings represents about 0.2% of the total corn plantings in the U.S. according to the National Agriculture Statistics Service.
These coated corn seed kernels contain significant pesticide content. One kernel of seed will contain enough systemic pesticides to kill more than 50% of bees exposed to the resulting plant, according to published LD50 values for honeybees – ranging from 22–44 ng/bee for clothianidin. This is called contact toxicity.
To test the connection between the bee deaths and the neonicotinoid Bt corn, the Purdue researchers planted corn fields in 2010 and 2011 with hives surrounding them. Half of the fields were planted in the neonicotinoid-treated corn, and half planted in untreated corn. The dead bees were found primarily in the hives surrounding the Bt corn fields, and the neonicotinoid pesticide residues from the dead bees and hives were primarily from the Bt corn pollen. This connected their toxicity and eventual death with the neonicotinoid pesticide-treated Bt corn.
The killing mechanism of neonicotinoid pesticides is that they are nicotinic acetylcholine receptor agonists. The pesticide excites these receptors among insects, causing their death following neurotoxicity. The application of neonicotinoids to seeds has been banned among some European countries because European researchers discovered this same connection between mass bee deaths and neonicotinoid pesticides over the last decade.
Recent beehive counts in Europe have revealed that bee hives have made a dramatic comeback since the ban was instituted.
The following brand names (some available in home garden sprays) also contain systemic neonicotinoids:
Actara, Platinum, Helix, Cruiser, Adage, Meridian, Centric, Flagship, Poncho, Titan, Clutch, Belay, Arena, Confidor, Merit, Admire, Ledgend, Pravado, Encore, Goucho, Premise, Assail, Intruder, Adjust and Calypso.
Bees pollinate more than 70 different crops – crops essential to our food supply. Without healthy bees, food supplies become more scarce. Recent data has revealed that more than a third of commercial beehives have been dying or gone missing every year since 2006 in the United States.
Concerned U.S. citizens are urged to take the following actions:
1) Check home pesticide products for neonicotinoids, and better yet, stop using chemical pesticides around the home and garden.
2) “Vote with your fork” by not buying foods made with genetically-modified Bt corn and other crops – which are often coated with neonicotinoid pesticides.
3) Write to congressional representatives and the Environmental Protection Agency. EPA’s Pesticide Information Center can be reached at firstname.lastname@example.org or 800-858-7378.
Krupke CH, Hunt GJ, Eitzer BD, Andino G, Given K. Multiple routes of pesticide exposure for honey bees living near agricultural fields. PLoS One. 2012;7(1):e29268.