Southeast Michigan fruit regional report – September 4, 2012

Record spotted wing Drosophila trap catch in fall red raspberries.


Drought conditions have returned to many fruit farms in east Michigan, with soil moisture supplies running much below normal. The areas affected by drought are not as widespread as was the case earlier this summer and the degree of wilting leaves is not as severe as it was a few weeks ago.

Our early, warm season is still running about two weeks ahead of normal in terms of growth stages, and more than three weeks ahead of normal in terms of growing degree day totals.

I am pleased to announce that a new Enviro-weather station at Flint, Mich., has been installed and is now operational. This will be a great aid to area fruit farmers. Thanks to the Ruth Mott Foundation and the Applewood Estate for funding and hosting this station.

East Michigan Growing Degree Day Totals for March 1 to September 3





Commerce (Oakland)




Emmett (St. Clair)




Flint (Genesee)




Lapeer (Lapeer)




Petersburg (Monroe)




Pigeon (Huron)




Romeo (Macomb)




Tree fruits

Apple harvest continues at the few farms that have a crop this season. Gala that were treated with Retain are being harvested, and Honeycrisp harvest continues. Growers are starting to harvest a few Golden Delicious. Apple harvest is very slow this season because the crop is so early, light and spread out. There are many farms where apple quality is a problem, mostly due to freeze damage, resulting in many small misshapen fruit. Fruit size has stalled at many farms due to drought stress.

Apple maggot trap catch continues and will do so for the rest of the fall. However, we are at a point of the season where apple maggots will go into diapause and, therefore, will no longer be a concern. Codling moth trap catch has remained very low to nonexistent for the last nine weeks.

Peach harvest of late season varieties is finishing up. Leaf yellowing and drop continues in trees that do not have a crop. A few blocks have so little foliage left that it looks more like late fall in terms of the degree of foliage remaining.

Sweet cherry and tart cherry leaf yellowing and drop is severe in some blocks, mainly due to a combination of cherry leaf spot disease and drought.

Small fruits

Raspberry harvest on fall-bearing varieties is finally ramping up at most farms; however, most farms still need several days of ripening before they can open again for the next picking. Spotted wing Drosophila trap catch has hit record numbers at many farms in the last few days, with one reporting 80 flies caught on one trap in the last week. A few growers are starting to see wormy berries and have had to stop harvesting for a few days. Growers need to use their trap catch numbers as an indication of their presence and to base control strategies on.

Over the weekend (September 1-2), MSU’s Rufus Isaacs updated the publication Spotted Wing Drosophila Management Recommendations for Michigan Raspberry and Blackberry Growers. The publication can be found online at MSU’s IPM Spotted Wing Drosophila website.

Blueberry harvest is wrapping up. Spotted wing Drosophila-infested fruit were an issue in the last two weeks at a few farms, where harvest came to an early end due to infested fruit.

Grape harvest is underway for table grapes. Concord types are well-colored at most farms.

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