San Diego Union-Tribune (Sunday)
BEEHIVE DIE-OFF BLAMED ON POISON
More than 3 million bees were killed by chemical used to exterminate termites and ants at construction sites
A mass beehive die-off in Escondido last year has been connected to fipronil, a chemical typically used to kill termites, according to a county investigation. But the mystery of how this insecticide resulted in 3 million pollinator deaths at the San Diego Bee Sanctuary remains.
Dominick Peck and Paul Gunn, co-owners of the San Diego Bee Sanctuary, had arrived at their honey-making apiary in Escondido on Sept. 20 to find that 65 of their 67 hives had died.
The two were shocked that their winged insects, which they spend more than 10 hours a day cultivating, had suddenly died. The county
Department of Agriculture, Weights and Measures went to the apiary to investigate what may have caused the die-off, including testing dead bees for chemicals.
Last month, the business partners learned of the results.
“It’s a fipronil incident,” Gunn said he was told by investigators. “Sometimes beekeepers will use fipronil, but we don’t. We don’t use any chemicals against ants or termites or anything, especially because we’re on other people’s land and I don’t want to put any kind of chemicals into it.”
According to Gunn, beekeepers may use a small amount of fipronil to stop ants from invading their hives or termites from eating the wood stands the hives are placed on.
Garrett Cooper, deputy director at the county department, said composite samples taken from the bees returned with 0.072 parts per million of fipronil — a dose far higher than the nanogram level lethal to the bees.
“With regards to bee die-offs, this was very rare,” Cooper said. “In the last two to three years, this is maybe the biggest one that I’ve heard of.”
James Nieh, a professor at UC San Diego and expert in the field of bee biology and evolution, said it remains unclear how the pollinators at the San Diego Bee Sanctuary became infected.
“Fipronil is a pesticide, specifically an insecticide that is often used for treatments, for example, at construction sites or buildings, when they want to kill termites or ants,” said Nieh. “It is used in agricultural fields, but that is not its normal use.”
According to his research of California Department of Pesticide Regulation data, the pesticide has been used heavily in local areas, although data after 2021 is not yet available.
Cooper said he and his fellow county investigators checked every angle during their analysis to find a cause for the bees’ deaths, looking at possible environmental factors, diseases and pesticides. However, once they landed on fipronil, they couldn’t find where the pesticide was used or how the bees came into contact with it.
“We’re not sure we can determine the source of where that fipronil came from or how they became exposed to it,” Cooper said. “We collected a whole bunch of foliage samples to see if it might have drifted (in the wind) and hit the sanctuary ... but none of those samples came back positive.”
Nieh said he also can’t be certain how 3 million bees became infected. Bees, both cultivated and feral, take the nectar they collect and pass it among themselves to create honey and can also collect water from the same source.
The professor theorized that the bees could have been exposed to the pesticide after collecting from surface runoff, when the pesticide was sprayed or injected into wood at a development. The surface runoff could have then congregated into a puddle or into a water supply used by the bees.
“Bees are not going to be hunting around in your basement or your foundations,” Nieh said. “But bees do collect water. And it’s possible that fipronil may, as part of the building treatment, have been inadvertently dissolved in water that these collect.”
The investigation, much
like the mass die-off of the bees, was unique, Cooper said. He said he has not heard of fipronil poisonings affecting many, if any, hives locally or in the state. But he said his department, and others like it across the state, take everything into account when conducting their investigations because of how important pollinators are.
Roughly three-quarters of the world’s flowering plants and about 35 percent of the world’s food crops depend on animal pollinators like bees, accounting for one in every three bites of food, according to a report from the U.S. Department of Agriculture. This results in not only a stable food supply worldwide, but billions of dollars in economic growth.
“There’s an interrelationship that allows for the continuity of agricultural businesses and these apiaries that help contribute to the food supply and trade,” Cooper said. “We don’t want to see these disruptions because it can really affect downstream.”
Peck and Gunn say they are committed to rebuilding their business and continuing their work at a second apiary in Valley Center after leaving their Escondido location because of the pesticide.
The San Diego Bee Sanctuary’s busy season is fast approaching, and they need to regain the number of colonies they lost so they can properly sell colonies to first-time beekeepers and contract pollinators out to farmers, Peck said.
They have had dozens of hives given to them from a fellow beekeeper and have continued to collect hives from peoples’ homes. The wild hives are then taken back to the San Diego Bee Sanctuary for rehabilitation. The two hope to distribute 400 boxes containing hives in the coming year.
“We did suffer a huge loss and it sucks, but there’s billions of bees in California,” Peck said. “And so the real way people can help is to not use chemicals on your house.”
Nieh said that he and his fellow apiary owners in the region are pushing San Diego to become a Bee City USA member. The nationwide project asks cities to commit themselves to protecting bee populations through policies and awareness campaigns.
“Bee cities” promise, among other things, to reduce pesticide use, host public awareness events and create a local committee consisting of volunteers and city staff to advise policy.
Last year, UC San Diego became a Bee Campus USA participant. Nieh said he and his fellow advocates are now awaiting a signatory from the city on the agreement, which would solidify San Diego as the largest city to do so in the nation, according to Nieh.