West central Michigan tree fruit update – April 22, 2025

Emily Lavely<lavelyem@msu.edu>, Michigan State University Extension - April 22, 2025

Bud development is slow and steady with the cool weather, but changes are still occurring as we inch closer to bloom.

Figure 1. Stage of tree phenology for apple, pear, cherry, peach and apricot in Oceana County on April 22, 2025. Photo by Emily Lavely, MSU Extension.

Weather update

Cooler weather has kept bud development moving slowly, but new leaf growth is still emerging across west central Michigan (Figure 1). Based on the Hart Enviroweather station for April 22, current growing degree day (GDD) accumulation is 185 GDD₄₂ and 67 GDD₅₀. Across the region, GDD accumulation is below the five-year average for the Hart Enviroweather station (Table 1) and right about average for the Sparta station (Table 2).

Warmer weather is forecasted for this week in the Hart area with highs in the 60s and lows in the 40s. For the Sparta area, highs will be in the 60s and 70s, and lows will be in the 40s and 50s. Across the region, there are slight chances of rain throughout the week.

Table 1. West central region: Current and five-year average GDD summary from Jan. 1- April 22. Numerical integration was used for degree day calculations.

Station	2025 GDD Base 42 F	5-yr Avg GDD Base 42 F	2025 DD Base 50 F	5-yr Avg GDD Base 50 F
Benona/Shelby	162	180	57	70
Elbridge/Hart	185	212	69	88
Fremont	203	228	77	93
Grant	246	255	74	111
Hart	185	208	67	85
Ludington	180	201	63	83
Mears	185	209	67	86
New Era	171	202	61	79
Shelby-East	182	204	68	82

Table 2. Grand Rapids region: Current and five-year average GDD summary from Jan. 1- April 22. Numerical integration was used for degree day calculations.

Station	2025 GDD Base 42 F	5-yr Avg GDD Base 42 F	2025 GDD Base 50 F	5-yr Avg GDD Base 50 F
Sparta	247	254	104	110
Alpine Twp/ Comstock Park	257	265	109	115
Sparta-North	240	254	97	109
Conklin/Wright	243	257	99	110
Kent City	232	244	93	104
Standale/Walker	281	292	122	131
Belding	251	259	106	115
Clarksville	279	278	120	123

Weather data was gathered from 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 (which may be searched by region) and Midwest Regional Climate Center website.

Crop update

Growers have been able to get out into the field to trim trees, clean up brush, plant trees and install trellis where needed. With more green tissue showing in apples, protective copper sprays were applied to protect new green tissue that emerged at the end of last week and over the weekend.

Apple varieties in Oceana County range from first green to half-inch green. Early varieties such as Zestar and Idared are at half-inch green, and later varieties such as Gala and Honeycrisp are at 0.25-inch green. As a reminder, half-inch green in apple is 205 GDD₄₂ for McIntosh based on over 30 years of observation from Sparta; other apple varieties will be ahead or behind McIntosh. Hart is at 185 GDD₄₂, and Sparta is at 247 GDD₄₂.

Tart and sweet cherry buds range from bud swell to green tip. There is still time to apply delayed dormant applications of oil or copper sprays to manage bacterial canker and early pests such as mites or scale insects.

Peaches are showing signs of swelling and green tip.

Pear varieties are showing signs of bud scales separating and swollen bud.

Pest and disease update

New Era: With cooler temperatures and slow bud development, emerging tissue in apple is at low risk for apple scab infection. Spores were first observed during the rain event on April 14-15 with three spores per rod. For rain on April 18-19, four spores were trapped per rod. We have had a couple wetting events, but lower temperatures require longer wetting periods for infection. With cool temperatures and low spore counts, infection risk has been low to date. However, with temperatures warming and more spores maturing to be ready for release, new tissue will need to be protected through fungicide coverage. Through the rest of the week, there are slight infection risks predicted for apple scab with rain in the forecast toward the end of the week in the Hart area. I will continue to check the spore trap and monitor spore release.

Sparta: According to Amy Irish-Brown with Valent U.S.A, “Apple scab spores are being monitored in a commercial McIntosh block located nearby the Sparta MSU Enviroweather station. For the rain event on April 9, an average of 44 spores per rod were caught. For the rain event on April 15, an average of one spore per rod was trapped. Heavy rains across the Ridge on April 18-19 lead to the first primary apple scab infection of the 2025 season. Areas south are on their second or third infection. Rainfall totals ranged from about 0.75 inch to over an inch. A total of 124 spores were trapped over the whole rain event.”

Similar to last week, the Trevor Nichols Research Center trapped a few adult green fruitworm this week, but green fruitworm is not a major pest in our area.

Red banded leafroller and plum curculio were also trapped on April 21 at the Trevor Nichols Research Center.

For more information about regional reports, please visit the Michigan State University Extension website.

This article was published by Michigan State University Extension. For more information, visit https://extension.msu.edu. To have a digest of information delivered straight to your email inbox, visit https://extension.msu.edu/newsletters. To contact an expert in your area, visit https://extension.msu.edu/experts, or call 888-MSUE4MI (888-678-3464).