West Central Michigan small fruit regional report – June 24, 2014

Strawberries are in full harvest with high yields and good quality. Fruit rot infections increase and require fungicide treatments. We have detected the first spotted wing Drosophila in strawberries. Growers should monitor to prevent fruit infestation.

Weather conditions in West Central Michigan over the last seven days have been hot and humid. Warm temperatures are prevalent and the daily average high temperature is 76 degrees Fahrenheit with the minimum at 62 degrees F. These temperatures have allowed for a growing degree day (GDD) accumulation of 1,254 base 42 F, and 756 base 50 F. In addition, there has been an increase in precipitation in the area. For the past week, five out of seven days have had more than three inches of rain in some places.

Regarding small fruit crops, the strawberry harvest in West Central Michigan is at its peak with high yields and very good quality. However, high temperatures and high humidity are creating problems related to fruit rots, mainly gray mold. Growers need to spray fungicides to prevent further damage. Switch and Elevate are good materials to control gray mold, but for other fungicide treatment alternatives, please consult the 2014 Michigan Fruit Management Guide (E-154).

Currently, no insect problems have been observed in strawberries, but growers need to be aware that there is a potential for spotted wing Drosophila (SWD) infestations, especially in day neutral strawberries. These plants have been in the field for a long time, and they could be the first place where SWD is found. Therefore, SWD monitoring in these fields is critical. So far, we have detected one single fly in one yellow sticky trap loaded with the synthetic lure in Ottawa County, but no fruit infestation has been detected yet.

Blueberries are sizing rapidly. In Allegan County the early season varieties are ripening very fast with fruit coloring, and 10 percent blue already showing up in some fields. So far, the crops look very good in the varieties of Bluecrop, and Duke. The variety Elliott seems to be the most affected by winter damage and the size of the crop might be smaller than observed in the variety Jersey, another variety that has had considerable winter damage.

So far, the SWD traps have been deployed in blueberries, but no SWD has been trapped in West Central Michigan so far. It is important that growers use the correct trap design and attractant recommended by the Michigan State University Extension small fruit team. Homemade devises lacking the proper design and attractant will result in failure of early detection of SWD infestation in your fields. If you have problems obtaining traps, you do not know how to build them, or if you have any other problems with your trapping program, please call your local Michigan State University Extension office for assistance.

There is also a good amount of information available online at our Michigan State University spotted wing Drosophila website. You may call Carlos Garcia at 616-260-0671, or email .(JavaScript must be enabled to view this email address) for assistance.

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