Colony Collapse Disorder (CCD): Pollinators, Pesticides, and Treated Seed

Colony Collapse Disorder (CCD): Pollinators, Pesticides, and Treated Seed

Honey bees are very important pollinators of a great number of ornamental and food crops. Unfortunately, honey bees have been suffering from population decline worldwide caused by a condition called “colony collapse disorder” (CCD). CCD is very concerning due to the critical importance of honey bees as crop pollinators.

Colony Collapse Disorder Bees

The exact causes of CCD are not fully understood; however, a number of different factors are likely involved. It is thought that a combination of interacting factors including environmental stresses, habitat loss, food quality (nectar and pollen), parasites (including two types of mite pests), diseases, and viruses all play a role in CCD. In addition, pesticide exposure is likely a factor, and certain pesticides are increasingly of concern, as they may have negative effects even when bees are exposed to low (sub-lethal) concentrations.

One of the most concerning classes of pesticides are called neonicotinoids, which are synthetic derivatives of nicotine. These are “systemic” pesticides. That means they are taken up by plants and spread throughout plant tissues as plants grow. There is concern that neonicotinoids can be found in the pollen and nectar of treated plants, and bees harvesting this nectar and pollen may harm their colonies.

Some reports online claim that neonicotinoid pesticides are the cause of CCD, but this has not been conclusively proven. CCD is a very complex problem and it is not fully understood. Research is ongoing, and more study is needed to fully understand CCD and the effects neonicotinoids and other pesticides have on honey bee health. There are calls to ban or restrict use of neonicotinoids without consideration for what pesticides would be used to replace them. In Europe there is a temporary ban on using some neonicotinoids on flowering crops, and this has resulted in increased pesticide use and significant losses in crops like oilseed rape (a type of mustard).

Neonicotinoid pesticides are primarily used on agronomic (farm) crops like corn, canola, sugar beets, soybeans, etc. They are most often used as a seed treatment in these crops. There are also neonicotinoid products labeled for use on landscape plants, including trees, shrubs, and flowers.

Neonicotinoids are toxic to bees, and new label requirements for neonicotinoid pesticides applied as a foliar spray require application in ways that minimizes exposure of bees to the pesticide. There have been some documented honey bee dieoffs caused by improper handling of neonicotinoid treated seed resulting in bees being exposed to planting dust which contains pesticide residues. Such applications have not followed label requirements and have resulted in fines to the growers making the improper (and therefore illegal) applications.


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