Northwest Michigan fruit update – June 24, 2025
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EmailIsolated hail hit northwest Michigan over the weekend. Growers are actively managing for diseases with warm and wet conditions. Pest numbers are also increasing with this weather.
Weather report
Northwest Michigan had the first real heat wave over the weekend when daytime temperatures hit 92.6 degrees Fahrenheit on June 22. In addition to daytime highs, the overnight temperatures are also hot: the low temperature on June 22 was only 78.7 F. The hot weather has also been accompanied by high humidity, making the weather seem even hotter. Temperatures are predicted to cool for the remainder of the week but hit the 80s on the weekend. The predictions are also calling for scattered showers this week, which will make disease control decisions difficult.
For 2025, the Northwest Michigan Horticulture Research Center has accumulated 1148.7 growing degree days (GDD) base 42 and 658 GDD base 50. We are behind our 35-year average but closer than we have been in a few weeks: 1178.5 GDD base 42 and 681.2GDD base 50.
The area received a lot of rain last Friday, June 20, and some Michigan State University (MSU) Enviroweather stations reported more than others. At the Northwest Michigan Horticulture Research Center, we received 1.62 inches of rain June 21. In most areas, there was enough rain to warrant new disease sprays to protect fruit and foliage from infection. That rain plus the warm and humid conditions in the forecast will keep growers on their toes to protect orchards from fungal diseases.
Unfortunately, the region was hit with another round of hail over the weekend. The Northwest Michigan Horticulture Research Center had hail, and our leaves are torn up. Some other areas had significant hail, and the damage is pronounced on both cherries and apples. Some of the hail was small, but some was close to golf ball size (Photo 2).
According to Jeff Andresen, MSU climatologist, the crazy weather pattern will continue through June and potentially through the end of September. This weather will be unsettled, and the medium range forecast is predicting more wet and warmer than normal conditions.
Crop report
The estimate for the tart cherry crop size from the Cherry Industry Administrative Board is 30 million pounds for northwest Michigan. West central Michigan was also estimating their crop to be 47 million pound. Growers in southwest Michigan estimate their crop to be 15 million pounds for a total of 92 million pounds of tart cherries in Michigan for 2025. Southwest Michigan growers are anticipating the start of tart cherry harvest around June 28. Growers in northwest Michigan are estimating to start tart cherry harvest around July 16. Next week is the National Cherry Festival.
Sweet cherries are sizing. All varieties are 15-18 millimeters (mm) at the Northwest Michigan Horticulture Research Center, depending on the variety. We have heard varied results of the size of the sweet cherry crop. Crop size seems to be variable between different varieties. Keep plum curculio out of these sizing fruits with the warm and wet weather in the forecast.
Gala and Honeycrisp fruit size jumped since last week when they were 21 and 22 mm; this week we measured Gala at 26 mm and Honeycrisp at 26 mm. We are approaching the window when apples are too big to thin. Some growers are still thinning apples, and some have already applied one thinner and going in with another to achieve optimal crop load. The crop load in apples is variable, and thinning has been a challenge this season. The carbohydrate thinning model shows a good window for thinning with the warmer conditions, but many growers are already reaching the fruitlet size that are too big for traditional materials to be effective.
Disease report
Fire blight. For the areas that had hail, treat apples for trauma blight. For fire blight management, especially after trauma like hail or strong winds, Michigan State University Extension recommends quick action. Ideally, apply bactericides within 4-12 hours of the trauma, as this timeframe allows targeting bacteria before they internalize and establish infection. Coppers are also good materials for trauma blight situations, but copper can cause russeting of fruit. Pruning should be done in dry weather, and pruning tools should be disinfected between cuts. Cut shoots 8-12 inches below the visible signs of fire blight.
Two treatments of the Apogee and Actigard combination provided excellent suppression of fire blight. Treatments of 2 ounces of Apogee and 1 ounce of Actigard per acre applied starting at king bloom petal fall and then again 10 days later suppressed fire blight lesion development. This strategy is critical to successfully control shoot blight, especially in high density orchards.
Apple scab. According to the MSU Enviroweather scab model, we are at 100% mature spores and 98% dispersed spores. The Grand Rapids region did not catch scab spores after the last rain on June 20, so they are calling the end to primary scab season on the Ridge. In west central Michigan, one more scab spore was caught on June 18, so they are not calling the end of primary scab. With the ample rain we received last Thursday, Friday and Saturday, we are calling the end to primary scab in northern Michigan.
Growers should be using materials such as Inspire Super, Cevya, SDHI fungicides or the new fungicide Axios. All materials have shown excellent efficacy in MSU scab trials. These single site fungicides should be tank mixed with protectants such as Captan or EBDCs. EBDCs have long preharvest intervals (PHIs): 77 days prior to harvest. Growers with early apple varieties should keep an eye on this PHI.
Here are the following links for RIMpro outputs from June 24, 2025:
Powdery mildew is showing up on terminals in apples at the station. Once the white mycelium is evident on leaves, this disease is difficult to eradicate. If powdery mildew is showing up in the orchard, fungicides should be used to protect new tissue from infection. This disease does not need rainfall for activity—hot and humid conditions are optimal for powdery mildew infections. For powdery mildew control, single site fungicides should be used at this timing: SHDIs (Miravis, Tesaris, Merivon), QoIs (Flint Extra) and DMIs (Rhyme). Many of the materials that growers will be using for scab control will also control PM.
Cherry leaf spot is more evident in the untreated trees in our efficacy trial. We had a leaf spot infection with high risk on June 18. The weather conditions will be prefect for all fungal growth, and cherry leaf spot is no exception. Actively manage for leaf spot with a preventative approach with the variable and isolated rainfall this week. Captan is an excellent material for leaf spot, and it continues to perform well in all efficacy trials, even when used alone throughout the season.
Copper materials are also rated excellent for leaf spot control. We have new data on the efficacy for leaf spot management comparing the different copper materials. Cool weather is a great time for copper use against leaf spot to minimize the potential for phytotoxicity to leaves.
Pest report
American plum borer. One moth was caught this week.
Lesser peachtree borer. This pest was caught for the fifth week, with an average of 23 moths per trap.
Greater peachtree borer. This pest was caught for the first time this week. Only three moths were caught.
Obliquebanded leafroller. This is the first time we have caught this pest this season. One trap had 17 moths, one trap had four and the last trap had zero moths. John Wise, MSU, caught a huge number of obliquebanded banded leafroller moths near the Trevor Nichols Research Center this week: 109 in one trap!
Black stem borer. None were caught in traps this week.
San Jose scale. We caught less male San Jose scale this week compared to just over one last week; we caught an average of three males. This insect has behaved a bit odd this year. Male catch is very low in many orchards where we are trapping, but the Trevor Nichols Research Center staff has captured lots of crawlers despite catching few males in traps.
Plum curculio. Growers should be controlling this pest at this time in cherry. At the Northwest Michigan Horticulture Research Center, we have observed sweet cherries at 15-18 mm, and plum curculio will oviposit into this fruit. Growers have reported plum curculio stings in cherry fruit, and we have oviposition damage in sweet cherries at the Northwest Michigan Horticulture Research Center. These insects are out and active, particularly with this warm weather. This pest can sneak up on cherry growers whose main focus is spotted wing drosophila, so be aware that plum curculio is active in orchards now. With the warm and wet weather in the forecast, some of the slow moving or less active females will be looking to oviposit into stone fruits. Growers should protect fruit from egglaying.
Codling moth. We caught an average of 3.3 moths per trap where one trap had five moths and the second trap had nothing. Codling moth has been caught for three weeks in a row at the Northwest Michigan Horticulture Research Center, so we are setting our biofix for June 3. Based on the codling moth model and the June 3 biofix date, we are at 20% egg hatch. We are actively managing for codling moth at the station. “Codling moth management options for Michigan apples” is a good article on codling moth.
Rose chafer. A lot of rose chafer are being seen in young blocks at the Northwest Michigan Horticulture Research Center. Many insecticides will knock down the beetle population effectively, but most are only rated as fair or good because of the beetles’ mobility and potential to re-infest. In tart cherry, Imidan is rated good for rose chafer; however, this material is among the most effective for spotted wing drosophila, so use other products to control rose chafer if you plan to use Imidan in your tart cherry block. Sevin is rated good in tart and sweet cherry. Some pyrethroid and neonicotinoid insecticides provide good knock-down of this pest, and the product Assail should provide some residual control due to its systemic properties.
Spotted wing drosophila. This pest was caught in traps today (June 24) in northwest Michigan (Photo 1). Traps in southwest Michigan have been catching this pest for a few weeks. In an MSU trial, spotted wing drosophila larva was found in fruit, and only two female flies were trapped this past week. This pest can infest fruit even if trap numbers are low—we have seen this in many years where we trap few adult flies in an unsprayed block but end up with significant infestation. However, our fruit in the northwest is still too green for spotted wing drosophila to oviposit, so we are at low risk for an infestation. The spotted wing drosophila model is predicting risk to go up on June 27, but tart cherry fruit are too green for females.
This weather is perfect for spotted wing drosophila population growth. The forecast is for warm and high relative humidity. We anticipate the population to grow very quickly under these conditions. This pest can have a single generation every seven days, and females can lay up to 300 eggs. With the shortage of fruit in the orchard, protect what is left from infestation; with a light crop, the spotted wing drosophila pressure will increase.
