An organic pesticide recently approved by the EPA and intended to help ease the decline of the bee population in the U.S. will be delivered in a novel way — by bees themselves as they alight on field and flower.

The fungicide Clonostachys rosea CR-7, also known as Vectorite, was created by Bee Vectoring Technologies in Canada for use on “high value” crops, such as strawberries, blueberries, almonds and sunflowers and is set to be rolled out this fall.

Beekeepers in the U.S. have reported a nearly 41 percent loss of their honey bee colonies over the past year, with winter losses the highest ever recorded. Some crops, including blueberries and cherries, are 90 percent dependent on honey bee pollination. Other bee-dependent crops range from carrots and tomatoes to onions and broccoli.

Honey bees pollinate $15 billion in food crops in the U.S. every year. Worldwide, three out of four crops across the globe that provide food for humans depend on pollinators.

The decline of bees has been linked to pesticides, and agricultural land is now 48 times more toxic to them than it was 25 years ago. In 2017, scientists were “alarmed” to discover fungicides, a type of pesticide targeted at mold, are one of the strongest factors linked to steep declines in bumble bees across the U.S.

The EPA was recently sued by environmental justice group Earthjustice after the government agency expanded the uses of “highly toxic” pesticide sulfoxaflor.

John Swanson, who runs a sunflower, soybean, corn and wheat farm with his son in northern Minnesota, has been experimenting with CR7 for the past three years as he worked with BVT to carry out trials.

“Most farmers are very concerned about using products that can hurt the environment,” he said. “Bees are important to the sunflower crop. I have worked with seed production for about 40 years, and bees are the only pollinator for hybrid sunflower seed production."

He said one of the main challenges to sunflower crops is a fungi called sclerotia.

“This fungicide suppresses sclerotia by about 40 percent," he said. "It’s the best product I’ve seen so far.”

Despite efforts to introduce bee-friendly pesticides, some experts say it will not solve the problem because farmers will continue to use insecticides, which are a form of pesticide, to kill crop-eating insects.

BVT uses bumble bees and honey bees to distribute Clonostachys rosea CR-7, a naturally occurring organism that blocks disease. The system, which has been in development for more than a decade, has bees walk through a tray dispenser of inoculating powder before they exit their hive.

The powder clings to the bees’ fur, and spores of the fungicide are dropped on plants as the bees travel. When absorbed by a plant, the fungicide enables it to block disease, such as botrytis in strawberries, which is the most widespread strawberry disease in California.

The EPA says Vectorite is the first EPA-approved pesticide to be delivered by bees.

Ashish Malik, CEO of Bee Vectoring Technologies, said he hopes Vectorcide will reduce, if not negate, the need for chemical fungicides. He said it has been evaluated under stringent criteria to ensure it has no adverse effects on bees.

Other companies have also come up with innovations to protect bee populations. Agribusiness giant Monsanto has developed an RNA interface that aims to kill parasites by disabling their genes, and Eltopia MiteNot monitors bee activity and delivers a blast of heat to stop male mites from fertilizing mite eggs on bee larvae.

The USDA regularly updates its list of permitted organic products, although natural substances are not necessarily less toxic than their synthetic counterparts.

But Malik said his company's product is the first to be delivered by bees and because the application is targeted, far less is needed compared to traditional spray applications.

“Bee vectoring is an all-natural approach that simply makes sense, and our vision is to develop this system to become a viable alternative to the inefficient practice of spraying crops globally,” Malik said in an interview.

Commercially managed bumble and honey bees are already used by farmers to pollinate crops.

“We piggyback on this, and are adding an additional value proposition on this already established industry practice,” Malik said

 BVT chose its particular microbial strain, Clonostachys rosea CR-7, because it can quickly colonize plant tissue around the flower of the plant.

“It protects crops against pathogens that enter and attack the crop in or through the flower area," Malik said. "This makes it an ideal choice for delivery using bees.”

Sheila Colla, a conservation biologist at the University of York, said BVT's method does not provide the answer to halting bees’ decline.

“Insecticides are applied to crops to stop pest insects from harming the crop, and I assume these farmers will continue to use insecticides in addition to these fungicides for fungal diseases," she said. “I don't see evidence of this replacing insecticides.”

Colla said using managed bees to deliver the product actually poses a threat to wild bee populations because pathogen spillover from managed bees to wild bees is one of the main threats to declining wild bee populations.

“It is most likely that our species, which have rapidly declined, such as the endangered Rusty-patched bumblebee, likely did so because they were exposed to a novel disease from managed bees,” she said.

While tech might be able to find solutions to issues with applying pesticides and dealing with pests, ensuring the sustainability of agricultural ecosystems will require a more holistic approach, Colla said.

“This includes protecting our native pollinator biodiversity for longterm sustainability," she said. "Biodiversity is resilience, especially under a changing climate.

“By moving our systems to relying more on managed bees, we put all of our eggs in one basket, so to speak," she continued. "If something happened to those few managed species and they collapse, as we saw with the Western bumblebee and with colony collapse disorder in U.S. honeybees, we put our ability to pollinate crops at risk.”