2017-05-18 / Front Page

Bug claimed 20% of tart crop in 2016

Benzie hit hard
By Eric Carlson
Of The Enterprise staff


NIKKI ROTHWELL, coordinator of the Northwest Michigan Horticultural Research Center, briefs the County Board on the threats posed by an invasive insect, the spotted wing drosophila, which attacks red tart cherries and is a “potential industry killer.” NIKKI ROTHWELL, coordinator of the Northwest Michigan Horticultural Research Center, briefs the County Board on the threats posed by an invasive insect, the spotted wing drosophila, which attacks red tart cherries and is a “potential industry killer.” Leelanau County is declaring war on the Spotted Wing Drosophila (SWD), a fruit fly that experts say could destroy the county’s — and the world’s — red tart cherry industry.

The coordinator of the Northwest Michigan Horticultural Research Center, Nikki Rothwell, told the Leelanau County Board of Commissioners Tuesday evening that some 20 percent of Leelanau County’s red tart cherry crop last year was destroyed by the invasive bug.

“This is really a national and global problem,” Rothwell added. “There was a 50-percent crop loss in Italy last year.”

The plight of locally grown tart cherries is also facing stiff competition from growers in Eastern Europe, as was outlined in an Enterprise story last week. Although farmers have taxed themselves to grow the concentrate cherry juice market more than five-fold to the equivalent of 240 million pounds of tarts, imports have supplied virtually all of that growth.


RED TART cherries, Leelanau County’s top crop, are especially vulnerable to the spotted wing drosophila, described by experts as a “potential industry killer.” RED TART cherries, Leelanau County’s top crop, are especially vulnerable to the spotted wing drosophila, described by experts as a “potential industry killer.” Located in Bingham Township, the research center that Rothwell heads is on the cutting edge of efforts globally to determine how SWD infestations can be controlled. Although multiple pathways are being explored, the best option now is for growers to spray insecticides on their crops – and keep spraying.

But the bugs will eventually develop immunity to insecticides, and humans don’t like insecticides on their food either.

Other solutions to the SWD problem are also being sought, including the introduction of other species that eat SWD, and the development of maleonly strains of the bug than cannot reproduce.

District No. 6 Commissioner Casey Noonan, who grows red tart cherries in southwest Leelanau County, said last season he was forced to spray insecticides on his red tart cherry trees repeatedly so cherries could be harvested.

“Our bills went up 25 percent last year just to control this insect,” Noonan said.

“It’s a potential industry killer,” Rothwell said.

Rothwell said the problem became so bad in neighboring Benzie County last year that one fruit farmer simply gave up and stopped spraying his trees to control SWD. As a result, the SWD population swelled and infested neighboring orchards, resulting in severe crop loss for many farmers.

“Right now, the folks in Benzie are seeing what can be done to put some teeth into requirements that efforts to control SWD not be abandoned — the consequences of not controlling this pest are so devastating,” Rothwell said.

Rothwell said she was not asking Leelanau County Commissioners to impose special rules on farmers or spend any money to help find solutions. She did ask them, however, to adopt a “Resolution of Support to Maintain the Required Funding of the Northwest Michigan Horticultural Research Station located in Leelanau County to assist with the Eradication of the Spotted Wing Drosophila.”

The resolution was to be forwarded to Leelanau County’s legislative delegation in Lansing, State Sen. Darwin Booher and State Rep. Curt Vanderwall. It was also being forwarded to state legislators representing other counties in northwest lower Michigan served by the research center.

The board voted 7-0 to adopt the resolution and directed the county clerk to forward it to legislators.

The resolution notes that northwestern lower Michigan produces 70-75 percent of the tart cherries grown nationally and is a “major economic driver in Leelanau County.”

The SWD is of East Asian origin and was first detected in Michigan in 2010. The female bugs cut slits into softskinned fruit such as the red tart cherry and leave eggs to develop inside. They also affect blueberries and other fruit crops in Leelanau County and elsewhere.

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