Fruit & Vegetable Magazine

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From the Editor: April 2016


March 22, 2016
By Marg Land


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Over the past few years, the global agricultural industry – including Canada – has been abuzz with discussion about the use of pesticides on crops and the health of honeybees. Various hypotheses regarding colony collapse disorder (CCD) and the decline of honeybee colonies have been suggested and tested, leading to the banning of some classes of pesticides.

But, according to the latest research from Europe, one pesticide may not be the only culprit.

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Researchers with the department of zoology at the University of Otago in New Zealand recently published a study in the journal Ecology examining what effect the organophosphate chlorpyrifos can have on honeybees. Insects were gathered from 17 sites around the Otago area. While levels of the pesticide in the bees were found to be well below the L50 point – the lethal dose for 50 per cent of the animals tested – “the formation and retrieval of appetitive olfactory memories was severely affected,” the researchers found.

“As learning and memory play a central role in the behavioural ecology and communication of foraging bees, chlorpyrifos, even in sublethal doses, may threaten the success and survival of this important insect pollinator,” they concluded.

In a study published recently in the Journal of Chromatography A, researchers with the National Veterinary Research Institute in Poland have discovered that European honeybees are being poisoned by up to 57 different pesticides.

“Bee health is a matter of public concern – bees are considered critically important for the environment and agriculture by pollinating more than 80 per cent of crops and wild plants in Europe,” said Tomasz Kiljanek, lead author of the study. “We wanted to develop a test for a large number of pesticides currently approved for use in the European Union to see what is poisoning the bees.”

Kiljanek and his team used a testing method called QuEChERS, typically used to look for pesticide residue on food, to analyze bees from 70 different poisoning incidents. They were able to test for 200 different pesticides simultaneously – about 98 per cent approved for use in the EU – plus additional compounds created when the pesticides break down.

Their results – 57 different pesticides were present in the bees. According to the study’s conclusions, “it is the broadest spectrum of pesticides and their metabolites, till now, detected in honeybees.”

“This is just the beginning of our research on the impact of pesticides on honeybee health,” said Kiljanek. “Honeybee poisoning incidents are the tip of the iceberg. Even at low levels, pesticides can weaken bees’ defense systems, allowing parasites or viruses to kill the colony. Our results will help expand our knowledge about the influence of pesticides on honeybee health and will provide important information for other researchers to better assess the risk connected with the mix of current pesticides.”

While the outcome of the project was to develop a new tool for studying which pesticides may actually be having a negative effect on honeybees, it has also shown that improving bee health isn’t as simple as banning one pesticide. The issue appears to be a bit more complicated than that.