A viral pathogen that typically infects plants has been found in honeybees and could help explain their decline. Researchers working in the United States and China have reported their findings in a recent edition of mBio, the online journal of the American Society for Microbiology.
Tobacco ringspot virus (TRSV), a pollen-borne pathogen, was found during routine screenings of commercial honeybees at a USDA laboratory, where further study revealed the RNA virus was replicating inside its honey bee hosts. Varroa mites, a bee parasite, also were found to carry the virus but were not infected, leading researchers to conclude that they aided the spread of the virus within the colony. The virus is even passed from an infected queen to her eggs.
The discovery is the first report of honeybees becoming infected by a pollen-born RNA virus that spread systematically through the bees and hives. Traces of the virus were detected in every part of the bee examined, except the eyes.
"The results of our study provide the first evidence that honeybees exposed to virus-contaminated pollen can also be infected and that the infection becomes widespread in their bodies," says lead author Ji Lian Li, at the Chinese Academy of Agricultural Science in Beijing.
Yan Ping (Judy) Chen, a bee pathologist at the USDA Agricultural Research Service laboratory in Maryland and lead author of the study stated, “I want to be cautious. The cause of colony collapse disorder (CCD) remains unclear. But we do have evidence that TRSV along with other viruses that we screen on a regular basis are associated with lower rates of over-winter survival.”
Beekeepers and environmental activists continue to focus on the neonicotinoid insecticides as the culprit of CCD. Despite increased pressure from environmentalists and beekeepers, the EPA continued to resist pressure in ’13 to follow Europe's lead and impose a ban on the neonicotinoids. It appears that the activists are resorting to state actions. The following state legislatures have had bills recently introduced restricting the use of neonicotinoid insecticides:
· Alaska: HB 224 would prohibit the use of neonicotinoid pesticides "unless the pesticide is contained entirely within a greenhouse," according to the bill.
· Maine: HP 1158 would place a two-year moratorium in the state on the use of neonicotinoid pesticides, ending on July 15, ’16, in order to allow a joint committee of the legislature to review the chemicals and their potential effects and, if necessary, craft legislation limiting their use.
· New Jersey: A 1373 would require the state's Dept. of Environmental Protection to prohibit the sale of neonicotinoid pesticides, citing their potential effects on pollinators. Those in violation of the bill would be subject to a $500 civil penalty for the first offense, and a $1,000 fine for every subsequent use.
· Vermont: S 232 would require the use of neonicotinoids be approved by the state's Secretary of Agriculture, and then the chemicals only could be used in the case of a threat to Vermont crops that could not be treated with another pesticide.
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