As Rhode Island Pollinator Species Decline, Pesticide Spraying Moves Into Backyards
October 18, 2021
Succumbing to the relentless pressures of habitat loss, climate change, and exposure to pesticides, the population of the American bumblebee (Bombus pensylvanicus), has declined by 89 percent nationwide. The news is far worse in eight states, including Rhode Island, where the American bumblebee has “completely vanished,” according to a recent story in the Smithsonian Magazine.
Once one of the most commonly observed pollinators across the United States, the remaining populations of American bumblebees are now so low that they are under consideration for designation as an endangered species. A petition to the federal government filed in August by the Arizona-based nonprofit Center for Biological Diversity seeks to protect the bees under the Endangered Species Act. The U.S. Fish and Wildlife Service is currently reviewing the petition.
Alan Gettman probably knows more than anyone about mosquitoes in Rhode Island. As the state’s mosquito abatement coordinator, Gettman oversees the trapping and testing of mosquitoes. Mosquitoes found to be carrying the West Nile virus or eastern equine encephalitis are identified at the Rhode Island Health Department Laboratory, and the Rhode Island Department of Environmental Management (DEM) issues weekly mosquito testing reports.
Gettman, who recently wrapped up the testing season, said the wet summer contributed to the large numbers of mosquitoes, but despite the larger mosquito population, only a small number of cases of West Nile virus were found.
“We’re up to five isolations of the virus in our mosquito samplings this summer, and that’s kind of normal, or maybe a little above normal,” he said.
A sixth sample, collected in Gloucester on Sept. 27, has tested positive for the virus. No samples taken this summer tested positive for eastern equine encephalitis.
Mosquito spraying, however, is a booming business.
A quick internet search for “mosquito testing in RI” turned up not a list of testing laboratories, but advertisements from companies that promise to eliminate them. Lawn-care companies have entered the lucrative business of mosquito control, and many other companies specialize in spraying for mosquitoes and ticks.
Some companies offer “all natural” yard treatments, but the chemicals most often used to kill mosquitoes are synthetic chemicals known as pyrethroids, not to be confused with pyrethrins, which are derived from a species of chrysanthemum.
Steven Alm, a professor of entomology at the University of Rhode Island, said pyrethroids will kill whatever insects they land on. A team of graduate students, led by Alm, recently found a single American bumblebee in Rhode Island — after about a decade of one not being observed here — but are keeping the location secret.
“Some of these mosquito products, for example, like the pyrethroids, yeah, if you hit the bees with them, and other beneficial insects, they’re going to be toxic to those as well,” he said.
Pyrethroids are safe to pollinators once the spray has dried and sunlight begins to break them down, so the number of non-target species killed by yard-spraying depends, to a large extent, on the skill and training of the applicator.
“If you’re not trained to avoid the flowers, for example, it could do some harm, especially to bees and parasitic wasps and lady beetles and things like that,” Alm said.
DEM requires certification for commercial applicators, but the agency also used to require formal training, which, DEM spokesperson Michael Healey said, is now optional.
“Since the inception of the pesticide safety program in the late 1970s, DEM did require training as a prerequisite for testing,” he said, “… someone challenged the requirement about five years ago … at which time DEM reviewed it and found it to be unenforceable because there was no statutory basis for us to require training. Since then, training has been voluntary.”
Alm said the lack of training is concerning.
“You know, you get these people that have not had training with p