Northwest Michigan fruit update – April 14, 2020

Cold weather continues this week and these cold conditions have slowed plant, pest and disease development.

Weather report

Spring has been slow to show up here in northwest Michigan, and Michigan State University climatologist Jeff Andresen says more unseasonably cool temperatures will continue through next week. Conditions will be warmer and drier than normal for this time of the year. There is a trough of air hovering over the Great Lakes region, which is causing the state to have continued cooler than normal weather. The weather is predicted to remain cool through the remainder of April; daytime temperatures will be in the 30s for this week but perhaps will climb into the 40s for next week. There is a chance of precipitation tomorrow and Thursday, April 15 and 16, but little precipitation in the forecast for the next week. The major area for concern will be the overnight and into the morning temperatures of tonight and Wednesday night, April 14 and 15. The cold temperatures are particularly concerning in more southerly regions of the state where crop development is much further along than we are here in northwest Michigan.

You can review Andresen’s report online at MSU Extension’s Fruit Weather Reports page.

Growing degree days (GDDs) through April 13, 2020








30 Yr. Avg.

















Crop report

With the continued cool conditions, crop development has been slow. Gala and Honeycrisp at the station are between dormant and silver tip. Montmorency tart cherry buds are starting to swell and show some green. Gold sweet cherry are at side green and Ulster and Emperor Francis are at bud swell. Growers are starting to receive shipments of trees for spring planting.

Pest report

This season we are pleased to have access to RIMpro to monitor apple scab development. Like last season, we have three sites connected to the RIMpro system, which include East Leland, Williamsburg and Benzonia. McIntosh green tip on average occurs around 110 GDD base 42 and most of the region’s apples are still between dormant and silver tip. When we set green tip biofixes for the area, we will begin publishing the RIMpro model outputs.

Overall, pests and diseases are generally not active at this time, and based on the forecast, it will still be some time before activity will pick up. In terms of crop development and management, we are still in the window for dormant sprays. However, oil should not be applied in the coming days as there is a risk of freezing temperatures for the remainder of the week. For more tips on dormant applications, review “Dormant oil for tree fruit pest management in 2015” from our colleague Amy Irish-Brown. 

Don’t forget that you can still sign up for the Spring 2020 Tree Fruit Webinars. On tomorrow’s webinar (April 15), we will host guest speaker Jason Deveau from the Ontario Ministry of Agriculture, Food and Rural Affairs for a lively presentation on spring sprayer preparations and configurations for air-assist sprays.

We also have a quick update on research. Some research has been approved for the Northwest Michigan Horticulture Research Center and these projects include spotted wing Drosophila research as well as cherry leaf spot trials. Our MSU fruit team has also been granted permission to run the statewide monitoring network for spotted wing Drosophila, brown marmorated stink bug and black stem borer.

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