Bees die needlessly as Zika prompts US state to spray pesticide

By Anna Nowogrodzki

It was an avoidable massacre. Beekeepers in Dorchester County, South Carolina, saw 48 of their hives killed off on 28 August. The culprit was a pesticide, sprayed from a plane with the aim of killing mosquitoes that can carry the Zika virus.

But South Carolina’s mosquito population isn’t yet known to carry Zika – and even if the virus is present, there are ways to kill the mosquitoes without killing bees.

In response to four local cases of Zika, Dorchester County sprayed a pesticide called Naled, a neurotoxin which kills adult mosquitoes and other insects. The four people infected all caught the virus before arriving in South Carolina: no one in the state has yet acquired Zika locally.

The aerial spraying killed millions of bees. Commercial beekeeper Juanita Stanley lost 46 hives, and a hobbyist beekeeper lost two. “Of course this is a tragedy,” says Michael Weyman at Clemson University, South Carolina, which is investigating claims by the beekeepers that the pesticide was misused.

Any actions that cause mass bee deaths are particularly concerning, given the fragility of bee populations in general – a consequence of the mysterious colony collapse disorder.

Bees can be spared by spraying at night instead of in the early morning. Bees don’t fly at night, and Naled only kills insects while they are airborne, says Mark Latham, director of Manatee County Mosquito Control in Palmetto, Florida, an area with commercially important beekeeping. Latham has carried out aerial spraying for 35 years, including of Naled, and almost always sprays at night.

The approach should work even though Aedes aegypti – the mosquito that can carry Zika – is a species active by day.

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