Southeast Michigan fruit update – August 18, 2026
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EmailBlueberries are winding down while peach harvest continues.
Welcome to the 21st in-season fruit article update for Southeast Michigan for the 2026 season. Throughout the season these updates will include information about the weather in the past week and the upcoming week, a fruit-by-fruit guide to current conditions with appropriate pest and disease updates, and other relevant observations.
General observations
Although conditions have remained generally hot and humid that humidity hasn’t translated to precipitation, much like the two prior weeks. We are expecting storms on Saturday, Aug. 22, but otherwise fair to warm conditions. High temperatures will mostly stay in the 80s for the next week while overnight lows will drop to the 50s over the weekend.
Growers are picking fall raspberries, Haven series peaches, and moving into mid-early apples like Ginger Gold. European style plums and more grape varieties are at full color. Powdery mildew is again the biggest disease risk this week, though there is also risk for cherry leaf spot and grape downy mildew. Brown marmorated stink bug damage has been detected in some orchards.
Michigan State University Extension educators recently published the 2026 apple maturity prediction dates, including the apple harvest prediction dates for southeast Michigan.
Our weekly video IPM updates have concluded for the season. See the recordings of the weekly fruit meetings for Southern Michigan on MSU’s Kaltura Media Space, including the final June 23 meeting.
Fruit-by-fruit conditions
Apples: We are in the main pattern of summer cover sprays and moving along with harvest of early varieties like Ginger Gold. Our main concerns at this time of year are powdery mildew, apple maggot, brown marmorated stink bug, and codling moth.
Blueberries: The main harvest season has wrapped up. Some growers with U-pick berries have some blocks remaining open.
Brambles: Fall raspberry and blackberry harvests continue. Poor pollination and crumbly berries have been seen at some sites in fall raspberries, which may be due to unsuitable weather conditions during bloom. Fruit rots and spotted wing drosophila management are the main concerns for production.
Cherries: Harvest has wrapped up in both sweet and tart cherries at farms that decided to harvest this year. Unharvested fruit can be a reservoir for spotted wing drosophila (SWD), so if you have other crops that are susceptible to SWD, like blueberries and brambles, you may want to remove them.
Grapes: Veraison has moved along in later winegrape cultivars like Petite Pearl with full color visible in many cultivars like Fredonia and Marquette. Some growers have put up bird netting for high-value cultivars.
Peaches and nectarines: We are moving forward in the Haven series of peaches, with most growers having passed Red Haven and moved into other cultivars.
New bulletin: “Best Practices for Peach Orchards with Reduced Crop Load”
Pears: Pears are sizing up in the region, with early Bartlett harvest expected in the next week or so in warmer areas. Local scouts have continued to report sightings of pear psylla adults in orchards.
Plums: European style plums are at full color while harvest of Japanese style plums has concluded.
Strawberries: Harvest is done in the region and most growers have already renovated.
Insect conditions
More in-depth information can be found by watching the latest weekly fruit meetings on MSU’s Kaltura Media Space (these may take a few days to upload after the meetings).
New MSU article: “Don't trust the calendar: Why trapping matters during unusual weather”
New MSU fact sheet: Managing Ambrosia Beetles in Apples
Aphids: Woolly apple aphid populations in apple are moving towards terminals and populations are building in blocks that have a history of aphid infestations.
Apple maggot: Continued catches of low numbers have been reported in the region (one to two per ball) for the last four weeks. Counts at Fennville remain low.
Blueberry maggot: Low catch reported in Fennville.
Borers: Catch of greater peachtree borer is down and counts of lesser peachtree borer are up in Fennville.
Brown marmorated stink bug: Adults along with damage have been observed in Southeast Michigan orchards. Because adults are active so close to harvest you need to pay close attention to your pre-harvest intervals.
Codling moth: Adult catches are climbing regionally and in Fennville, including some sites over threshold.
Grape berry moth: Counts in Fennville have dropped.
Japanese beetle: Counts have been declining regionally but have stayed stable in Fennville.
Mites: Mite counts have been dropping regionally. European red mites and rust mites are responsible for some bronzing in orchards. Two spotted spider mites will put out webbing.
Oriental fruit moth: Counts have stayed low in Southeast Michigan but slightly rose in Fennville.
Pear psylla: Increased adult and nymph activity has been observed in orchards again along with some evidence of damage.
San Jose scale: We are seeing waxed up scales in the region, meaning that the control window has shut. Counts of adult males in Fennville have climbed.
Spotted lanternfly: Look for nymphs in parts of the state that have documented populations (Detroit, Monroe County, Oakland County).
Spotted wing drosophila: Consistent counts in traps in Southeast Michigan. This pest often prefers fruit to the traps, so low trap counts do not necessarily mean low risk in fruit.
Disease conditions
Apple scab: We don’t anticipate risk for secondary scab infections this week.
Cherry leaf spot: We anticipate slight risk this week from Aug. 9-20. See this 2024 article on cherry leaf spot management.
Fire blight: Since we have moved out of bloom there is low risk in apples and pears, however if there is hail damage growers should spray for fire blight.
Grape downy mildew: We anticipate slight risk on Aug. 19.
Grape powdery mildew: We are expecting moderate to severe risk from Aug. 23-25.
Phomopsis: In blueberries, the Phomopsis fungus is active from bud swell until after harvest.
Powdery mildew of apple and pear: There will be airborne conidia all week and models indicate moderate to severe risk from Aug. 22-24.
Seasonal weather update
In the last week, Southeast Michigan has seen an average of 4.4 hours of rain accumulating to 0.5 inches of precipitation.
| Liquid Precipitation Accumulation Mar. 1- August 18, 2026, issued August 18, 2026 | ||||
|---|---|---|---|---|
| Station (County) | Rainfall Total (in.) Current | Hours with Rainfall Current | Rainfall Total Average (5 Yr.) | Hours with Rainfall Average (5 Yr.) |
| Commerce (Oakland) | 17.2 | 236 | 18.5 | 272 |
| Deerfield (Monroe) | 23.1 | 247 | 16.3 | 258 |
| East Lansing MSU Hort (Ingham) | 18.6 | 264 | 17.0 | 264 |
| Emmett (St. Clair) | 17.9 | 270 | 16.5 | 267 |
| Flint (Genesee) | 17.7 | 247 | 17.7 | 276 |
| Freeland (Saginaw) | 18.2 | 222 | . | . |
| Hudson (Lenawee) | 18.9 | 260 | 16.6 | 164 |
| Ithaca (Gratiot) | 19.1 | 250 | 15.0 | 251 |
| Lapeer (Lapeer) | 16.9 | 259 | 17.1 | 286 |
| Linwood (Bay) | 19.9 | 256 | 15.0 | 249 |
| Pigeon (Huron) | 16.4 | 259 | 14.6 | 265 |
| Richville/Frankenmuth (Tuscola) | 19.5 | 238 | 16.8 | 247 |
| Romeo (Macomb) | 19.5 | 245 | 19.1 | 260 |
| Sandusky (Sanilac) | 16.3 | 241 | 14.7 | 285 |
| Average of stations in this region: | 18.5 | 249.6 | 16.5 | 257.2 |
| Difference in Liquid Precipitation Accumulation from Mar. 1 observed August 11 and August 18, 2026; issued August 18, 2026 | ||||||
|---|---|---|---|---|---|---|
| Rainfall Total (in.) | Rainfall Total (in.) | Hours with Rainfall | Hours with Rainfall | |||
| Station (County) | 11-Aug | 18-Aug | Difference | 11-Aug | 18-Aug | Difference |
| Commerce (Oakland) | 16.9 | 17.2 | 0.2 | 234.0 | 236 | 2.0 |
| Deerfield (Monroe) | 21.6 | 23.1 | 1.5 | 238.0 | 247 | 9.0 |
| East Lansing MSU Hort (Ingham) | 18.4 | 18.6 | 0.2 | 259.0 | 264 | 5.0 |
| Emmett (St. Clair) | 17.6 | 17.9 | 0.3 | 266.0 | 270 | 4.0 |
| Flint (Genesee) | 16.6 | 17.7 | 1.1 | 244.0 | 247 | 3.0 |
| Freeland (Saginaw) | 17.7 | 18.2 | 0.6 | 219.0 | 222 | 3.0 |
| Hudson (Lenawee) | 18.3 | 18.9 | 0.6 | 248.0 | 260 | 12.0 |
| Ithaca (Gratiot) | 19.0 | 19.1 | 0.0 | 248.0 | 250 | 2.0 |
| Lapeer (Lapeer) | 16.5 | 16.9 | 0.4 | 255.0 | 259 | 4.0 |
| Linwood (Bay) | 19.5 | 19.9 | 0.3 | 253.0 | 256 | 3.0 |
| Pigeon (Huron) | 16.4 | 16.4 | 0.0 | 258.0 | 259 | 1.0 |
| Richville/Frankenmuth (Tuscola) | 18.8 | 19.5 | 0.7 | 235.0 | 238 | 3.0 |
| Romeo (Macomb) | 19.0 | 19.5 | 0.5 | 237.0 | 245 | 8.0 |
| Sandusky (Sanilac) | 16.2 | 16.3 | 0.1 | 238.0 | 241 | 3.0 |
| Average of stations in this region: | 18.0 | 18.5 | 0.5 | 245.1 | 249.6 | 4.4 |
In the short term, we are expecting scattered storms on Saturday with fair weather before and after. Highs for the next week will be in the low-80s while overnight lows will be in the mid-60s for most of the week before dropping over the weekend. We are expecting the rest of August to exhibit above normal temperatures and above normal precipitation.
Our regional average growing degree day accumulation for the season are about seven days ahead of the long term normals and about three days ahead of the five-year average. In the last week we accumulated on average 213 GDD at 42 F, 191 GDD at 45 F, and 156 GDD at 50 F (see table below). Read this Michigan State University Extension article to learn more about degree days: Understanding growing degree-days.
| Degree Day Accumulation Mar. 1-August 18, 2026 Forecast from Aug. 19-25, 2026; issued August 18, 2026 | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Station (County) | Degree Days Base 42°F Current | Degree Days Base 42°F Average (5 Yr.) | Degree Days Base 42°F Forecast | Degree Days Base 45°F Current | Degree Days Base 45°F Average (5 Yr.) | Degree Days Base 45°F Forecast | Degree Days Base 50°F Current | Degree Days Base 50°F Average (5 Yr.) | Degree Days Base 50°F Forecast |
| Commerce (Oakland) | 3158 | 3009 | 3348 | 2755 | 2616 | 2925 | 2130 | 2011 | 2265 |
| Deerfield (Monroe) | 3438 | 3272 | 3615 | 3012 | 2862 | 3168 | 2346 | 2229 | 2467 |
| East Lansing MSU Hort (Ingham) | 3226 | 3068 | 3411 | 2815 | 2670 | 2980 | 2177 | 2058 | 2307 |
| Emmett (St. Clair) | 2925 | 2837 | 3107 | 2537 | 2449 | 2699 | 1941 | 1855 | 2068 |
| Flint (Genesee) | 3320 | 3176 | 3514 | 2915 | 2776 | 3088 | 2285 | 2158 | 2422 |
| Freeland (Saginaw) | 3033 | 3013 | 3214 | 2642 | 2623 | 2802 | 2033 | 2022 | 2158 |
| Hudson (Lenawee) | 3302 | 3153 | 3477 | 2889 | 2755 | 3043 | 2249 | 2142 | 2368 |
| Ithaca (Gratiot) | 3239 | 3147 | 3430 | 2838 | 2750 | 3008 | 2213 | 2136 | 2348 |
| Lapeer (Lapeer) | 3118 | 2977 | 3301 | 2724 | 2587 | 2886 | 2114 | 1988 | 2241 |
| Linwood (Bay) | 2781 | 2798 | 2956 | 2399 | 2418 | 2553 | 1816 | 1838 | 1935 |
| Pigeon (Huron) | 2857 | 2854 | 3035 | 2478 | 2474 | 2635 | 1889 | 1892 | 2011 |
| Richville/Frankenmuth (Tuscola) | 3126 | 3068 | 3308 | 2730 | 2673 | 2892 | 2116 | 2061 | 2243 |
| Romeo (Macomb) | 3194 | 3040 | 3386 | 2792 | 2645 | 2963 | 2170 | 2036 | 2305 |
| Sandusky (Sanilac) | 2990 | 2903 | 3167 | 2604 | 2519 | 2760 | 2006 | 1931 | 2127 |
| Average of stations in this region: | 3122 | 3023 | 3305 | 2724 | 2630 | 2886 | 2106 | 2026 | 2233 |
| Difference in Degree Day Accumulation from Mar. 1, 2026 observed August 11 and August 18, 2026; issued August 18, 2026 | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Station (County) | Degree Days Base 42°F | Degree Days Base 42°F | Degree Days Base 42°F | Degree Days Base 45°F | Degree Days Base 45°F | Degree Days Base 45°F | Degree Days Base 50°F | Degree Days Base 50°F | Degree Days Base 50°F |
| 11-Aug | 18-Aug | Difference | 11-Aug | 18-Aug | Difference | 11-Aug | 18-Aug | Difference | |
| Commerce (Oakland) | 2940 | 3158 | 218.2 | 2558 | 2755 | 197.0 | 1969 | 2130 | 161.3 |
| Deerfield (Monroe) | 3222 | 3438 | 216.4 | 2817 | 3012 | 195.3 | 2186 | 2346 | 160.3 |
| East Lansing MSU Hort (Ingham) | 3007 | 3226 | 219.0 | 2618 | 2815 | 197.3 | 2015 | 2177 | 162.1 |
| Emmett (St. Clair) | 2727 | 2925 | 198.2 | 2360 | 2537 | 176.8 | 1799 | 1941 | 141.9 |
| Flint (Genesee) | 3090 | 3320 | 230.2 | 2706 | 2915 | 209.2 | 2110 | 2285 | 175.0 |
| Freeland (Saginaw) | 2823 | 3033 | 209.9 | 2453 | 2642 | 188.9 | 1879 | 2033 | 154.1 |
| Hudson (Lenawee) | 3092 | 3302 | 210.0 | 2701 | 2889 | 188.3 | 2096 | 2249 | 153.4 |
| Ithaca (Gratiot) | 3019 | 3239 | 220.0 | 2639 | 2838 | 198.8 | 2049 | 2213 | 163.8 |
| Lapeer (Lapeer) | 2900 | 3118 | 218.5 | 2527 | 2724 | 197.1 | 1952 | 2114 | 162.2 |
| Linwood (Bay) | 2586 | 2781 | 195.5 | 2225 | 2399 | 174.0 | 1677 | 1816 | 139.5 |
| Pigeon (Huron) | 2657 | 2857 | 200.4 | 2298 | 2478 | 179.9 | 1745 | 1889 | 144.4 |
| Richville/Frankenmuth (Tuscola) | 2912 | 3126 | 214.5 | 2537 | 2730 | 192.8 | 1958 | 2116 | 157.8 |
| Romeo (Macomb) | 2977 | 3194 | 217.4 | 2596 | 2792 | 196.2 | 2008 | 2170 | 161.8 |
| Sandusky (Sanilac) | 2783 | 2990 | 207.3 | 2418 | 2604 | 186.2 | 1855 | 2006 | 151.0 |
| Average of stations in this region: | 2909 | 3122 | 213 | 2532 | 2724 | 191 | 1950 | 2106 | 156 |
Watch Jeff Andresen's weekly agricultural weather forecast reports
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.
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.
