Neonicotinoids and CCD

Beekeepers have long suspected the role of the neonicotinoid insecticides in the great upsurge of honey bee colony die-offs that have continued since 2006. Named Colony Collapse Disorder, the loss of honey bee colonies has persisted for eight years in spite of efforts by researchers to identify a cause and by beekeepers to replenish their hive numbers. According to the Bee Informed Partnership’s recently released report, http://beeinformed.org/2014/05/colony-loss-2013-2014/, annual losses have averaged an unsustainable level of nearly 30 percent. A relatively small-scale study by Harvard School of Public Health, http://www.bulletinofinsectology.org/pdfarticles/vol67-2014-125-130lu.pdf, reveals interesting findings. Honey bee colonies exposed to either of two low levels of neonicotinoid insecticides, imidacloprid or clothianidin, abandoned their hives during the winter, defining symptoms of Colony Collapse Disorder. This report contrasts somewhat from the results of a previous study on the effect of pesticides that lead to susceptibility to the honey bee gut pathogen, Nosema ceranae. The larger study, reported in PLOS ONE, http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0070182#authcontrib, finds large numbers and high levels of pesticides in honey bee hives. The researchers found 35 different pesticides in sampled honey bee pollen and high levels of fungicides.

Until recently, fungicides, chemicals designed to fight fungal infections, were considered safe for honey bees. Recent studies are finding fungicides to have an adverse effect on honey bee health, often making insecticides and miticides more toxic to bees. In the PLOS ONE study, fungicides were found to lead to Nosema infection. Needless to say, the search for the cause of Colony Collapse Disorder has revealed the complexity of the problem. There are many factors contributing to honey bee health, including nutrition, parasitic mites, pest insects, viral, fungal, and bacterial diseases, and environmental chemicals. Studies are finding insecticides, miticides, fungicides, and herbicides in the bee hives. Combinations of chemicals and breakdown products of chemicals are often highly toxic to bees. Peace Bee Farm has participated in a number of the studies. Today, catalpa trees secrete nectar from the flowers and nectaries on the leaves.

--Richard

Clothianidin Studies

The neonicotinoids are insecticides developed with the hope of being less harmful to wildlife and beneficial insects than the available insect killers, the pyrethroids and organophosphates. The neonicotinoids came into widespread use with the understanding that they would not kill beneficial insects like the honey bee and bumblebee. The use of neonicotinoids coincides with the die-off of honey bees and significant reductions in bumblebees. Two studies linking honey bees’ having difficulty in navigating from flowers to the hive confirm that neonicotinoids impair bees’ senses. The studies are reported by The Washington Post at http://www.washingtonpost.com/national/health-science/new-bee-research-details-harm-from-insecticide/2012/03/29/gIQAZrnGjS_story.html. The studies find that bee hives exposed to low levels of neonicotinoid insecticides have fewer bees and bumble bees produce markedly fewer queens. Bayer CropScience, a manufacturer of neonicotinoids, calls the studies inconsistent with their findings. Beekeepers and the Center for Food Safety petitioned the Environmental Protection Agency to ban the use of clothianidin that the EPA approved using Bayer’s tests.

Neonicotinoids are generally applied as a seed coating. The systemic action of the insecticide causes the poison to be distributed throughout the plant including the nectar and pollen, highly attractive bee foods. Traces of neonicotinoids are taken back to the bee hive by foraging bees. While beekeepers in the United States are taking annual honey bee colony losses of one third each year, the effects are often more subtle than total colony failures. Colonies are often described as simply not thriving. Bee populations may be low; bees may have shortened life expectancies; or hives may lack sufficient bees of appropriate foraging age. Each of these situations leads to colonies that are susceptible to diseases and parasites. With small populations, colonies don’t produce surpluses of honey. Bee hives used for pollination service fail when graded according to bee population. With the ever increasing use of neonicotinoid insecticides that have been shown to have a detrimental effect on pollinators, the crops, lawns, and golf courses flourish while honey bee colonies, native bees, and beneficial insects quietly disappear.

--Richard

Pesticides Enter Bee Hives

Indiana experienced a massive honey bee die-off during 2010 resulting from poisoning by clothianidin, an insecticide highly toxic to honey bees, which is widely used on corn. Honey bees do not forage corn, a wind-pollinated grass, for nectar. However, they readily fly through corn tassels collecting poisoned pollen on their bodies when the plants have been treated with systemic insecticides. Clothianidin is in a class of insecticides called “neonicotinoids,” nicotine-based neurotoxins that are sprayed on foliage, sprayed on the soil, or coated onto seeds to kill gnawing or chewing insects that eat foliage or other plant parts. Systemic insecticides are carried throughout a plant and poison all plant parts, including nectar and pollen. Purdue University researchers studied the Indiana bee die-off to determine how neonicotinoids are transported from corn fields to honey bees and bee hives. The scientists identified several methods of insecticide contamination of bee hives near neonicotinoid-treated Indiana corn fields. Most corn is planted with seed coated with systemic insecticides. Talc is added to mechanical planters to prevent seeds from clumping. The scientists found clothianidin levels up to 700,000 times the lethal dose for honey bees in talc dust exhausted from planters. Also, significant levels of insecticide were found in the soil of corn fields as well as fields not currently planted in corn. Neonicotinoids are considered persistent; they remain toxic long after use. Outside the corn fields, dandelions, wildflowers attractive to honey bees, were also found to contain clothianidin.

Clothianidin was found in pollen stored in nearby bee hives. An exceptionally toxic effect occurs when honey bees gather clothianidin-contaminated corn pollen from fields treated with common fungicides, a widespread practice in North America. Dead bees found surrounding the hives contained clothianidin, either eaten by the bees or contacted with the bees’ bodies. The researchers caution that “sublethal doses of insecticides can weaken bees and increase susceptibility to key parasites or pathogens.” The study by Krupke et al. may be viewed at http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0029268. Today’s photo: clothianidin-treated broom corn.

--Richard

Clothianidin

Clothianidin is an insecticide belonging to a relatively new class of pesticides known as neonicotinoids. These nicotine-based chemicals are systemic in action, meaning that they are taken up through a plant to poison all of its parts. They are of great concern to beekeepers around the world because they poison the nectar and pollen consumed by honey bees and other pollinators. Clothianidin is often coated onto the seed of crops. It is in widespread use in the United States as an insecticide on corn, the nation’s largest crop. Other crops treated with clothianidin include canola, soybeans, sugar beets, sunflowers, and wheat. While corn, a grass, provides no nectar, it does produce a large amount of pollen, which is very attractive to honey bees. The use of clothianidin has steadily increased since its conditional registration in 2003. Beekeepers have experienced heavy winter die-offs from that time to the present.

The EPA quietly presented Bayer with full registration of clothianidin in April of this year following a seriously flawed trial funded by Bayer. The trial, conducted in Canada, placed hives near canola plots treated with clothianidin and untreated control plots. Remarkably, both plots were located so close together that the honey bees had free access to both. EPA scientists questioned the validity of the trial. Others experts analyzing the trial found significant flaws in its design: corn produces much more pollen than does canola; corn pollen is more attractive to honey bees; and canola is a minor crop in the US, while corn is the most widely planted crop. The neonicotinoids, including imidacloprid, are suspected by beekeepers and many scientists as contributing to honey bee colony collapse disorder. Clothianidin is a persistent pesticide, meaning that it remains in the environment for a long time, and the pesticide is highly toxic to honey bees. You may read the report at http://www.grist.org/article/food-2010-12-10-leaked-documents-show-epa-allowed-bee-toxic-pesticide-. Without independent investigation, the neonicotinoids remain suspects in colony collapse disorder. Clothianidin is banned in Germany, France, Italy, and Slovenia.  Today’s photo: clothianidin-treated corn.

--Richard