Corn planting using insecticide- coated seeds was linked to honeybee deaths, according to a study by researchers at Italy’s University of Padova.
The scientists found honeybees flying over fields where the coated corn was being planted were intoxicated by particles containing neonicotinoid insecticides vented by pneumatic seed planters, they wrote in a study published in the journal Environmental Science & Technology.
Beekeepers from China to the U.S. have experienced honeybee-colony deaths in recent years that may be linked to multiple factors, including insecticides, the United Nations’ environmental agency reported last year.
“Experimental results show that the environmental release of particles containing neonicotinoids can produce high exposure levels for bees, with lethal effects compatible with colony losses phenomena observed by beekeepers,” the researchers led by Andrea Tapparo from the university in Padua, northern Italy wrote.
Planters emit “significant” amounts of insecticide coating particles during corn sowing, and observations have indicated a “close link” between spring deaths of bees and use of pneumatic drilling machines, according to the study.
Honeybees were exposed to the insecticides by prompting them to fly over the fields to a sugar-solution dispenser, as well as by placing caged bees in the field being planted, according to the study.
About 30 seconds of exposure of single caged bees to the air flow emitted by the fan of the drilling machine, similar to one to two flights across the sowing field, always caused acute lethal effects, the study found.
The research was funded by the University of Padova and the Italian Agriculture Ministry, the researchers wrote.
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