21 Mar 2016

More pesticides research needed - bee scientist

8:37 pm on 21 March 2016

Research showing a pesticide called chlorpyrifos could threaten honeybees is not surprising and shows a need for research on other chemicals, a honeybee scientists says.

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Chlorpyrifos could stunt bees' ability to look for nectar, threatening their long-term survival. Photo: AFP

Plant and Food Institute honeybee scientist Mark Goodwin said new research into the pesticide showed 'sub-lethal' effects that would not kill a bee outright but could threaten the hive.

"When we looked at pesticides historically it was always just a question of 'did it kill bees or did they survive after being treated or not', but honeybees are a much more complex organism than that."

"And it's not a surprise that there are a whole lot of sub-lethal effects that are turning up."

Chlorpyrifos was routinely used on grass grub, Argentine stem weevil, onions and berryfruit and a 2013 study showed it was in air, water and plant samples across the country, Mr Goodwin said.

The leader of a recent Otago study, Elodie Urlacher, said they fed bees doses of chlorpyrifos that were considered 'safe' and put them through performance tests.

She said the bees were not as responsive to odours, and because bees relied on memory mechanisms to target flowers it could stunt their ability to forage for nectar, and therefore survive.

Mr Goodwin said the research was concerning.

"Anything that can affect the way their whole hive operates can have an impact on them, for example they have to communicate with each other, they have to remember where they've been foraging and where their hive is."

Doctor Goodwin said in most cases with pesticides the Plant and Food Institute was not even asking all the questions about potentially sub-lethal effects, but in the future it would be.

He said people should be careful not to spray pesticides when crops or plants were flowering.