Taking Steps towards Reducing the Risk to Pollinators
A high level of concern was raised in the spring of 2012 regarding bee kills and corn planting. Many growers are asking what actions they can take to help reduce the risk of bee kills this spring during planting. We will try to clarify the situation, and give the best recommendations we can provide at this time.
In the spring of 2012, coinciding with corn planting, there were approximately 200 incidences of what was likely acute poisoning of honey bees in Ontario. Representatives from the Ministry of Environment (MOE), Pest Management Regulatory Agency (PMRA), and the Ministry of Agriculture and Food (OMAF) and the Ministry of Rural Affairs (MRA) investigated affected bee hives, taking bee samples for residue analysis by PMRA. Though final results have not been released, PMRA's initial lab results indicate "that pesticides used on treated corn seeds may have contributed to at least some of the 2012 spring bee losses that occurred in Ontario, however, there is still additional information being collected". It is important to note that they have found no cases of off-label use by growers. It is also important to note that, though the analysis indicates the presence of clothianidin (active ingredient in Poncho), thiamethoxam (active ingredient in Cruiser) breaks down to metabolites that include clothianidin. Virtually all corn seed sold in Ontario is treated with some form of the insecticides in question.
Many factors may have contributed to these incidences. Environmental conditions and planting practices during the 2012 planting season may play a significant role. Unfortunately, without being present in each field at the time of planting to collect data, there may never be conclusive evidence as to route(s) of exposure to bees. However, results indicate that honey bees were somehow exposed to corn seed insecticides. So how can a bee come into contact with a seed insecticide during planting?
One of the more likely routes is dust. Research from Purdue University and other jurisdictions in Europe have found evidence that dust coming from the exhaust of high pressure air-assisted corn planters contained particles of neonicotinoid (eg. Poncho or Cruiser) seed insecticides. Many factors can contribute to the contamination of the dust including abrasion of the seed from the planter lubricant (eg. talc), quality and formulation of the polymer seed coating (sticker), and rough handling of the seed bags causing chaffing of the seed coat. Planting on dry, windy days may also help to carry the "fugitive dust" greater distances. Bees can come into contact with the contaminated dust while flying across the field during planting or from the dust settling on water sources or nearby flowers that they are foraging on.
What can corn producers do to help reduce the risk of bee kills when planting? The following are actions that should help reduce the production of contaminated dust during planting, and consequently (hopefully) reduce the exposure of bees to this dust. There is no guarantee that these actions will prevent bee kills from happening during planting. Many of these are best management practices that growers should be following anyway, given they are applying pesticides when planting treated seed.
Again, following all of these recommendations does not guarantee that there will not be future bee kill incidences at planting. These are the best suggestions we can offer based on the information available to date. We will continue to modify these recommendations as more information is made available, and research and technology is developed to address the issue. Updates will be provided on the Field Crop News site at: http://fieldcropnews.com/
Note: Any suspect bee kill incident taking place during spring planting in Ontario in 2013, should be reported to Linda McIntosh, Regional Manager - Pesticide Compliance Program - Health Canada at:
For more information:
Toll Free: 1-877-424-1300