West central Michigan tree fruit update – April 28, 2026
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EmailSweet cherries, tart cherries and peaches are in bloom this week across west central Michigan.
Weather update
Bud development has moved steadily over the past week across west central Michigan (Figure 1). Based on the Hart MSU Enviroweather station for April 27, current degree-day (DD) accumulation is 348 DD42 and 166 DD50. At the Sparta MSU Enviroweather station, current DD accumulation is 442 DD42 and 238 DD50. Across the region, DD accumulation is above the five-year average for the Hart and Sparta Enviroweather stations, and we are about a week ahead of normal. Last week, daytime highs were in the 60s and 70s, and nighttime temperatures remained warmer with lows in the 50s and 60s overnight.
This week started out warmer on April 27 with rain coming in Monday evening into Tuesday, April 28. Temperatures will be cooler this week than last week with highs in the upper 40s to low 60s in Hart and Sparta. Low temperatures will be in the upper 30s to 50s. Across the region, dry conditions are forecasted for the rest of the week.
Listen to the weather update from Jeff Andresen, MSU climatologist, at the Fruit & Nuts Weather page from MSU Extension.
Weather data was gathered from MSU Enviroweather.
More information and reports on normal weather conditions and departures from normal can be found on the NOAA Climate Prediction Center website, NOAA U.S. Climate Normals website, NOAA Climate Normals Quick Access Page.
Crop update
Field conditions are drying out. It has been easier to get crew members and machinery in the fields to trim trees, chop brush, plant trees and install trellis. Timing for bloom thinning is here for peaches and apples if needed for your orchard blocks.
Some growers have brought in honey and bumble bees for pollination. Honey bees will forage at temperatures at 65 F or warmer. Bumble bees and solitary bees will forage at temperatures 5-10 degrees cooler than honey bees. As we approach bloom, use practices that minimize pesticide exposure to bees. Find tips and guidelines to minimize bee pesticide exposure in the following articles from Michigan State University Extension:
Apple varieties in Oceana County range from king bloom to tight cluster. Early varieties such as Zestar and Idared are at king bloom, and later varieties like Gala and Honeycrisp are at tight cluster or open cluster. In Sparta, early varieties are at full bloom, and later varieties like Gala and Honeycrisp are at king bloom.
Growers are continuing to assess potential damage from cold temperatures on April 19-20. As a reminder from last week, damage will depend on the stage of development and the environmental variability across orchard blocks at the time of the cold event. Scout block by block to determine the damage in apple and other tree fruit crops. Damage can occur at a range of temperatures depending on stage of development. It’s important to look at the center of the flower to see if the pistil is damaged. See this article on evaluating frost or freeze damage and assessing the impact of cold temperatures on early fruit development.
Apple thinning programs should be considered as we get closer to bloom. Thinning of apple can start with pruning by removing excess fruit buds. Earlier thinning will improve fruit size and quality. Carbohydrate and nutrient resources available early in the season are divided between the number of fruit buds on the tree. By removing excess buds, more resources are available to remaining buds. While it is still early and freeze damage is still being evaluated in some apple blocks, begin thinking about thinning strategies for this season. See this article on general apple thinning recommendations and decision-making tools.
Apple scab risk is predicted to be low this week in Hart according to the RimPro model due to dry conditions this week. For the Hart MSU Enviroweather station, risk for apple scab infection was low during the rain event on April 24. The wetting event was for 6 hours, but 10 hours of wetting were needed for infection at the average temperature of 59.5 F. Only 11 spores per rod were counted for Hart.
There were 5 hours of wetting during the last rain event on April 28 from midnight to 5 a.m., and spore release was low. Because the average temperature was 57.4 F, 10 hours were needed for infection, so an infection event did not occur. There were infection periods at other locations in west central Michigan due to longer wetting hours. For example, an infection event was predicted at the Shelby-East MSU Enviroweather station.
The Sparta MSU Enviroweather model shows no apple scab risk for the rain event on April 18. Wetting hours needed for infection were 11, but 10 hours of wetting were met. Only 8 spores were counted for this event. For the wetting event on April 27, there was a light infection event that occurred according to the Sparta Enviroweather statement.
Some growers have applied early copper in apple and pear to knock down bacterial populations of the fire blight pathogen, Erwinia amylovora. Dormant and delayed dormant sprays help manage fire blight primarily if it was present the previous season, particularly in young, high-density plantings. The MSU Enviroweather model predicted some fire blight risk for the Sparta area if trees were in bloom, but EIP values ranged from 20 to 29 from April 24–28, below the recommended 70 EIP threshold for treatment. As flowers continue to open over the next few weeks, you can monitor infection risk through the Enviroweather model.
Tart and sweet cherry buds range from tight cluster to full bloom. With rain events, European brown rot (blossom blight) management may be needed, particularly under cool, wet conditions. Infection can begin in the popcorn stage before bloom. Treatment should include two applications, one at white bud and the other at full bloom. See more information on managing European brown rot. Managing American brown rot with fungicide application may also be needed in warmer temperatures above 65 F.
The risk for cherry leaf spot in tart cherry is currently low but will start to increase as bract leaves are emerging. Cherry leaf spot is caused by the fungus Blumeriella jaapii. This fungus overwinters on the ground in diseased leaves. Fungal ascospores are released in spring during prolonged wetting events. According to George Sundin, Michigan State University tree fruit pathologist, spores can infect as soon as bract leaves emerge. Spores infect through open stomata, and stomates on bract leaves were shown to be open when they emerged from buds.
Peaches are at first bloom or full bloom in some varieties. During bloom, fungicide applications against brown rot will be needed. Rusty spot (powdery mildew) management may also be needed in peaches, particularly if disease pressure was high in 2025. Now is a good time to put up mating disruption if you have not done so yet. Oriental fruit moth traps should be placed in peach blocks to monitor for first catch and set the biofix date.
Plum is at first bloom or full bloom in plum varieties in west central Michigan.
Pear varieties are at bud burst and first white. Now is the time to manage pear psylla and San Jose scale. Applications to manage pear scab can also be included this week to cover new green tissue before the next rain.
Additional pest and disease information
Green fruitworm were trapped in low numbers this week—two adults per trap. One red-banded leafroller was also trapped.
Oriental fruit moth were trapped at the Trevor Nichols Research Center with an average of 13.5 adults per trap. First catch of plum curculio was also observed at 13 adults per trap.
For more information about regional reports, please visit the Michigan State University Extension website.
This work is supported by the Crop Protection and Pest Management Program [grant no 2024-70006-43569] from the USDA National Institute of Food and Agriculture. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture.
