UCSD: ‘Bee safe’ pesticide could harm certain honey bees

SAN DIEGO – A group of UC San Diego researchers announced Wednesday that a pesticide billed as “bee safe” could actually threaten certain honey bee demographics, especially when used in combination with other chemicals like fungicides.

Sivanto, developed by Bayer CropScience AG, was designed to kill agricultural pests and not harm pollinators like bees. Farmers are allowed to use Sivanto on blooming crops because of its design, but it could still harm honey bees known as foragers because it was only tested on bees inside hives, according to the research team.

A representative of Bayer CropScience could not immediately be reached for comment.

The researchers said in-hive bees are generally younger and foragers are generally older bees. While Sivanto was tailored to not harm younger in- hive bees, foragers would still bear the brunt of its effects, according to the researchers, who published their study in Wednesday’s issue of the journal Proceedings of the Royal Society B.

“Our results highlight the importance of assessing the effects pesticides have on the behavior of animals, and demonstrate that synergism, seasonality and bee age are key factors that subtly change pesticide toxicity,” said UCSD postdoctoral fellow Simone Tosi, one of the study’s two co-leaders.

The researchers found that forager bees that interacted with crops dosed with Sivanto and a common fungicide were four times more likely than younger, in-hive bees to die or and show atypical behaviors like poor coordination and apathy. The bees also suffered more harmful effects during summer than in spring, Tosi said.

Sivanto is currently available in 30 countries in North and South America, Africa, Asia and Europe, and 65 other countries plan to approve it for use in the near future, according to the researchers.

“The idea that this pesticide is a silver bullet in the sense that it will kill all the bad things but preserve the good things is very alluring but deserves caution,” said professor James Nieh, the study’s other co-leader.

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