While viruses and other pathogens were deemed potentially responsible for the ongoing bee colony epidemic called colony collapse disorder (CCD), scientists from the US Department of Agriculture (USDA) did not discard the potential effects of pesticides in this epidemic as well.
A recent report from the USDA's Agricultural Research Service (ARS) found that a higher total load of pathogens--viruses, bacteria and fungi--appears to have the strongest link with Colony Collapse Disorder found so far. There was no association between increased pesticide levels and CCD, the study indicated.
Still, the ARS scientists said the study cannot show whether the higher pathogen load was involved in the cause of CCD or was a result of CCD. The epidemic could still be driven by several factors including pesticides, they said.
Current and future studies will now include focusing on combinations and synergistic effects of factors, such as the synergistic effects of Nosema and pesticides, and of pesticides and other pathogens.
"The primary aim is to help narrow future efforts that attempt to identify the cause of disease. This study suggests that future, longitudinal studies should focus on monitoring parasite (varroa mite), pathogen, and pesticide loads while quantifying pesticide tolerance in study populations. More specific studies that investigate potential interactions among pesticides and pathogen loads are also warranted."One ongoing research from the University of Illinois is to identify the specific honey bee genes responsible for pesticide detoxification and determine if there is an interaction between pesticides and compounds in pollen, honey, or propolis (a resinous mixture collected by bees) and subsequent ability of bees to tolerate pesticides.
Researchers from Pennsylvania State University, University of Illinois, and Michigan State University are also investigating the interactive effects of relevant pathogens and pesticides on honey bee health, said ARS.