How pheromones are reducing pesticide use in Quebec apple orchards

Stéphane Cataphard, an apple producer in Quebec's lower Laurentians, used to spray his orchards with insecticides to protect the fruit from the codling moth five, even six, times a year.

But not any more.

"Last year we just sprayed once," he said while sorting Macintosh apples at his warehouse in St-Joseph-du-Lac, 50 kilometres northwest of Montreal. "This year we hope to reduce it to zero."

Cataphard is among a growing number of apple producers in the province turning to insect pheromones – the chemicals females emit to attract their mates – to protect their crops from infestation by the moth's larvae, which burrow into apples and can ravage crops.

More growers signing on

The provincial government is backing the pilot project with financial incentives to apple growers, and that money is proving persuasive: Last year 30 growers tried the pheremone treatment. This year, there are 100.

It sexually frustrates the insects because they can't find each other and mate.- Acadia University biology professor Kirk Hillier

"Since we reduce the pesticides, it's beneficial for the environment, it's beneficial for the workers in the orchards because they are less exposed to the pesticides," said Maryline Courchesne, a consultant with the group Agropomme, which is encouraging producers to adopt the technology.

Courchesne has been visiting Quebec apple orchards, installing thin plastic rings containing pheromones onto tree branches, in a process called mating disruption, to target the codling moth.

"We will create a cloud of pheromone on top of the orchard so the male will not be able to find the female to mate and reproduce," said Courchesne. 

Or, as Kirk Hillier, a biology professor at Acadia University in Wolfeville, N.S., puts it: "It sexually frustrates the insects because they can't find each other and mate."

'Not actually killing anything'

Hillier has studied insect pheromones for years and says their use in pest control is growing. 

"The real benefit is that this is not insecticidal at all, you're not actually killing anything," he said. 

"Effectively you're modifying the behaviour of the insect to prevent a second generation, the damaging generation, from coming along."

Courchesne says one of the barriers is the cost of the pheromones. 

They cost up to $500 per hectare – five times more than the insecticide for codling moth.

Under the provincial program, apple growers are eligible for up to $10,000 a year in subsidies.

Cataphard is convinced he may be able to save money in the long run, if he can further cut down on spraying. 

Pheromones are also used in some orchards in Atlantic Canada, Ontario and British Columbia, and they've seen great success in outside of Canada, including in the state Washington and in Italy.

Hillier believes it will be adopted by an increasing number of producers.

"Over time, I think the market for these things is only going to grow, because of the greater need from the public to have chemical free fruits and vegetables," Hillier said.