The raspberries at Millar Berry Farm were perfect, ready to be picked and sold across southwestern Ontario, when the growers discovered their hard work would yield nothing.

The spotted wing drosophila, an Asian fruit fly that burrows into berries and turns them to mush, had taken over the crop on the London-area farm, despite careful monitoring.

"It's pretty devastating. We've put in so much work and now we have to abandon the whole crop," Matt Millar said.

The fruit fly first started causing trouble in Ontario five years ago, attacking not only raspberries but other berries including strawberries, but this season seems to be the worst on record.

Raspberry growers taken by surprise

The Spotted Wing Drosophila first appeared in Ontario five-years ago but in 2017, the invasive fruit fly has caused more trouble in the berry patch. (Ontario Ministry of Agriculture, Food and Rural Affairs)

"I have heard from growers this season that they're [here] earlier and are more of a challenge this year," said Erica Pate, a fruit crop specialist with Ontario's ministry of agriculture.

Paid said some raspberry growers may have been taken by surprise by how early the fruit flies did arrive, and may not have monitored for the bug soon enough.

There are no insecticides registered for the spotted wing drosophila in Ontario but the ministry does say keeping the patch clear of brambles, picking regularly off the bush and the ground, and applying other vineyard pesticides can help to keep the blight away.

It adds up to a lot more work for farmers

Millar Berry Farm explains it was doing all of that but still couldn't keep up with the fruit fly.

After more than 30 years of producing the berries, the loss of the summer crop has left the family feeling frustrated, contemplating abandoning the fruit like other farmers in the province have already done.

"Raspberries were one of the easier crops to manage before this pest arrived," said Kevin Schooley, executive director of the Ontario Berry Growers Association.

"A lot of growers have just stopped growing them."

Crop specialists across North America are working to control the pest, with local agricultural experts urging farmers to contact them at the first sign of the spotted wing drosophila.

Raspberry shortage?

Raspberries are produced twice each year, the Millar's crop being lost at the end of the first, summer harvest.

Matt Millar is concerned the fruit fly will find its way into the fall berry patch which he said would definitely affect prices for consumers.

"This is not an isolated incident because other growers are posting on our Facebook page that they're also experiencing it and they're done for the season."