HONEY BEE TOXIC INTERACTIONS WITH FORMULATION 'INERTS' AND PESTICIDE RESIDUES FREQUENTLY FOUND IN U.S. APIARIES

No single stress factor has been identified as the causal agent for honey bee Colony Collapse Disorder (CCD). This work will address if another major crop pollutant that co-occurs across classes of pesticides, 'inerts,' may alter toxicity of frequently found pesticides in honey bee foods, and indicate if new pesticide registration requirements should be implemented to insure pollinator safety in agricultural landscapes. Agrochemical formulations usually contain inerts at higher amounts than the active ingredients, and these penetrating enhancers, surfactants and adjuvants have not been evaluated in regard to bee exposures and toxicities. Inerts often enhance the pesticidal efficacy as well as inadvertent non-target effects of the active ingredient after application. Given the synergistic nature of certain chemicals, we are concerned that active ingredients may effect honey bees differently depending upon the inert ingredients in a particular product formulation or in certain combinations found in field use patterns. The fact that some inert ingredients may indeed be more toxic than active ingredients such as in formulations of the herbicide glyphosate makes this issue especially important for the health of honey bees and other pollinators. We have found unprecedented levels of miticides and agricultural pesticides in honey bee colonies from across the US and one Canadian province. While these samples were not part of a full-scale landscape or grower-level survey, the data contained here is the largest sampling of pesticide residues in N. American bee colonies or worldwide to date. With an average of 7 pesticides in a pollen sample, the potential for multiple pesticide interactions affecting bee health seems likely. While exposure to many of these neurotoxicants elicits acute and sublethal reductions in honey bee fitness, the enhancing effects of these active ingredients in combination with 'inerts' and their direct association with CCD or declining bee health remains to be determined. There is a new tendency to market pesticide blends including seed treatments that contain multiple classes of insecticides or fungicides, or their mixed combinations. These blends usually require proprietary adjuvants to achieve high efficacy and broadly control many pests. The impact of these potentially synergistic blends on non-targets including bees cannot be fully understood without knowing the identity of proprietary inerts. To address if these major crop pollutants alter toxicity of frequently found pesticides in honey bee foods, we will identify and quantify key formulation ingredients in the hive, test their short- and long-term toxic effects on brood and adult honey bees in lab and field, and communicate the results of our study to US beekeepers, growers, extension specialists and other researchers. Inert ingredients which are potentially hazardous need to be redefined by EPA in terms other than inert. For the sustainability of honey bees, other pollinators and beneficial insects, it is vitally important that these inert compounds be disclosed and their effects investigated.