It’s the bug to watch: Less than one-sixteenth of an inch long, the ladies fly around with serrated saws, the men with dots on their wings.
Last September the state caught the spotted wing drosophila here for the first time, by the half-dozens.
This summer, less than a year later, Monmouth traps bagged up to 3,000 a week.
The fruit fly newcomer would be an annoyance like its cousins if not for one major difference, according to experts: The spotted wing drosophila cuts a small hole in ripening fruit to lay eggs. The fruit, to the naked eye, can look fine for another day or two.
“If this was just another fruit fly that only attacked rotten fruit, we’d say no big deal,” said David Handley, vegetable and small fruit specialist for the University of Maine Cooperative Extension, based at Highmoor Farm in Monmouth.
“Because you’re picking fruit that looks perfectly sound and you put it on the kitchen shelf and the next morning you come out there’s maggots swimming in a soup, you’re going to be an unhappy customer and you’re not going to go visit that grower again,” Handley said.
For blueberry growers, its arrival could be particularly worrisome. Growers are used to spraying crops up to two times a season, but keeping the spotted wing drosophila at bay could mean spraying twice a week.
“This could have huge impacts on the wild blueberry industry,” Handley said. “This is a game-changer.”
He’s part of a team that received a $50,000 federal grant to study the fly next year.
At a recent regional meeting of small fruit experts in New York, “this was the hot topic,” said Eric Sideman, crop specialist for the Maine Organic Farmers and Gardeners Association. “Everyone is applying for money for grants to do research on this topic. Extension people are out visiting farms all over to assess the damage and get a handle on what kind of damage there is. It’s so new.”
The fruit fly, native to northern Asia, was first spotted in California in 2008, according to Jim Dill, a UMaine Cooperative Extension pest management specialist and professor of biological sciences.
Last year in the wake of Hurricane Irene, Dill set traps around raspberry fields, red cups with apple cider vinegar and apple juice and yeast concoctions.
“A lot of times, things come in after hurricanes,” he said.
Dill found Spotted Wing Drosophila in small numbers at four Maine locations. This year, he started trapping around strawberries in June. The flies didn’t bother that crop. Numbers didn’t start to grow, and grow, until late July.
“We’re assuming the winter does knock the population back and it takes awhile to build up, so the late-season small fruit crops are the ones that are of concern: blueberries, fall raspberries, blackberries,” Dill said.
Add chokecherries, elderberries, peaches and grapes to that list. The flies don’t appear to bother cranberries, apples or bananas.
The female spotted wing drosophila has a serrated egg-depositor that saws into soft-skinned, ripening fruit. It can lay 300 eggs during its 14-day lifespan.
“You can see how the population would explode,” Handley said. “In each of those eggs there’s a little white maggot in one of your berries, and they don’t stop there.”
One very early estimate from the wild blueberry industry: The flies could affect up to 20 percent of the crop, he said.
The extension plans to survey farmers in early October for a more accurate damage count. Blueberries in Maine are a multimillion-dollar industry. It’s too early to know the effect on growers and prices.
“Raspberries are a fairly expensive fruit, anyway,” Dill said. “Now, if you’re spraying twice a week it might double the cost of them.”
He has heard growers say they plan to hang it up.
Sprays exist for both traditional and organic farmers but brands have to be rotated with care; the fly can quickly develop resistance.
Dill said that he has found spotted wing drosophila this year everywhere he has set traps. The next year will be spent on research: Do some sprays work better than others? Could small netting work? Should growers harvest earlier? Is there a parasite that might develop a taste for the fly?
“As a grower, do you really want your income stream to stop at the end of July?” Handley said. “It’s pretty hard to make it as a farmer that way, unless you’re growing things that this thing won’t take an interest in.”
He added, “We don’t have a good answer for this one yet. We’re kind of in the position, unless you’re willing to let the crop go, you’ve got to protect it. Hopefully, research will send us down a road where we can find a good answer, but it’s pretty dark at the end of the tunnel right now.”
Dill’s best advice for consumers: Refrigerate your produce.
Traps can be made at home, he said, with a soda bottle, a piece of paper rolled up as if to create a funnel, a little apple cider vinegar and a few drops of detergent.
Just great. Another pest to contend with…..As if we don’t have enough of them to deal with already! I hope they find a way to control those things without forcing the prices of produce to skyrocket even higher than it already is.
“I hope they find a way to control those things…”
And without poisoning us, our children, our water supplies…
Oh yes, absolutely. I hope they find a beneficial insect (or organism) out there that enjoys nothing more than a nice tasty meal of fruit flies. lol
The real problem is not locally grown fruit but imported fruit at the super markets. If you stop to notice when in the market you will see the fruit sections crawling with the little buggers. Watch the fruit and veggies that are not refrigerated( stacked or displayed in the isle) when you bring them home then now you have spread the problem.
I know! I can’t count the times I’ve brought home fresh fruit from the supermarket only to see those things buzzing around shortly after I put it in the fruit bowl. Those things are so annoying!
As a very small scale raspberry grower, I can attest to the damage done by these insects. My entire Fall raspberry crop has failed costing me over a thousand dollars in income. Virtually every ripe berry has maggots inside it. I tried spraying with an organically acceptable chemical with no success. I refuse to use harmful sprays. My remaining hope for 2012 is that with cold weather coming it will knock down this fly and allow me to harvest the tail end of my crop before a hard freeze comes. I will likely dig up and remove all of my plants and perhaps replant with an earlier maturing variety in hopes of getting harvestable berries before the fly population again explodes.
“One very early estimate from the wild blueberry industry: The flies could affect up to 20 percent of the crop, he said.”
A another cost of Global Warming.
Crop yeilds with the warming were fantastic…..including high bush blue’s.
I have Broccoli ‘trees’ I’ve just pruned, they just keep growing and growing.
The lobster harvest was way up, too, so how’s that worked out for the fisherman ?
It was the national corn and apple crops that are Mother Nature’s object lesson, this year.
So it goes.
I wonder if we can get more details on this trap recipe (red cups with apple cider vinegar and apple juice and yeast concoctions)? I’m wondering if these could help me rid my home of the fruit flies that appear around harvest time every fall? Any information is appreciated. Thank you.
Orchards at Common Ground were empty of apples and the Japanese beetles riddled the leaves. ,there and in my small orchard…..maybe the two pests will cancel each other out? I can dream can’t I?
My Mom also went to that fair and told me the exact same thing about those trees. She was shocked to see the condition of them. I waged a daily battle with japanese beetles on my own apple trees (and rose bushes) for several weeks this year. I can’t even count how many met their deaths in my coffee can of water and dish soap. The same with those awful lily beetles, too.