For those weary of hearing about infected mosquitoes, beetles killing elm trees and blight on tomatoes, hold on – a new plague has surfaced.
The spotted wing drosophila, often called a vinegar fly, is wiping out whole crops of
soft fruits – blackberries, black raspberries, blueberries, sweet and tart cherries and strawberries.
The tiny insect has the ability to penetrate firm, unripe fruit and is boring its way into berries and laying its eggs.
The fruit looks fine until it ripens and is picked, then the damage surfaces and fruit turns to mush.
White worms – maggots – come out of the fruit, Tom Ford, Penn State Extension horticulture educator, explained.
“We’ve had widespread reports in Cambria and Somerset counties,” he said. “It’s a pest we’ve been tracking for a number of years. You may not even know you have a problem.”
That was the case at Blackberry Bottom, a berry farm just off Interstate 99 at Cessna, Bedford County, where more than 5,000 pounds of ripe blackberries plus untold unripe berries had to be pulled from the bushes and burned in a pit.
“It’s been devastating,” said Shannon Foor. “I first heard of it at a growers meeting late last winter.”
At that meeting, Penn State horticultural experts talked of how devastating the insect
could be, but it wasn’t until Foor got a phone call from someone who had purchased berries this summer that he fully grasped the problem.
The berries, destined for pies and jam, had been placed in a pail in the buyer’s garage. Later, when the cook went to retrieve the fruit, she was met with a gruesome sight.
“There were a number of small, white worms crawling in the bucket,” Foor said. “(When I heard that) I thought back to sitting in that conference and I remembered I saw something that looked like fruit flies around the bushes.”
Blackberry Bottom boasts 70,000 blackberry bushes on 20 acres at Bedford Reinforced Plastics, about five miles north of Bedford. Foor is business development manager.
The farm was started as a way for the company to promote a new type of fruit trellis it had developed. It planted the bushes in summer 2011 and carefully covered them for the winter with high hopes for a bountiful commercial product this summer.
Foor said crews immediately harvested thousands of pounds of ripe blackberries after learning of the disease. They put the infested berries in a pit, added some kerosene and struck a match.
Next, they initiated an extensive insecticide spraying program in hopes of destroying the insect and its breeding ground.
But then Foor learned that the insects bore into the fruit and lay eggs long before it ripens. So he and his crew went back into the fields, where they stripped the bushes of all fruit and destroyed that as well.
The insect has no impact on the health of the bushes and Foor has stepped up his spraying regimen – every seven to 10 days through late fall.
Experts say the infected fruit is not dangerous to humans if ingested and Foor said he’s not discouraged over this sharp learning curve.
“I’m ready for winter to be over and spring to come so we can start again,” he said.
Controlling SWD, as the infestation is commonly referred to, involves getting rid of all infected fruit and establishing a regular insecticide spraying program.
Unlike common fruit flies, attracted to overripe or rotting fruit, the SWD goes for the soft-skined, healthy fruit in various stages of ripening as a nest for eggs that can number more than 300 over a two-month period, according to Penn State experts.
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