July 24, 2025

By Becky Wiepz and Dan Kielar

Alert! High Spotted Wing Drosophila trap counts and confirmed presence in sweet and tart cherry fruit

Station Updates

Cherry harvest is ongoing throughout the county!

UW Madison/Extension Updates

Historic Growing Degree Day Comparison

Date 7/23	2021	2022	2023	2024	2025	20-year avg.
Base 50	1215	1110.5	1174.5	1221.5	1139	1169

GDD₅₀ continues to stay 2-3 days behind the 20-year average.

Recent Weather at Peninsular Ag Research Station

Date	Max Temp(℉)	Min Temp(℉)	Max Wind Gust(mph)	Daily Rain Total(in)
7/16	79.2	59.5	23.3	0.02
7/17	70.9	51.4	21.0	0.02
7/18	70.3	47.5	15.0	0.0
7/19	73.8	61.0	12.8	0.38
7/20	76.8	51.8	9.4	0.0
7/21	73.2	52.5	11.6	0.0
7/22	77.4	63.1	17.2	0.0
7/23	78.3	66.7	31.1	0.42

Upcoming forecast may result in continued infection periods for fungal and bacterial pathogens due to predicted rain events and warm temperatures.
If you’d like to see weather data for your area, visit https://wisconet.wisc.edu/

Apples

Growth Stage: Fruit continues to size
Seasonal Update: Foliar nutrient samples should be collected from Honeycrisp at this time and other varieties in the next few weeks for most accurate results. Most blocks are going into second generation codling moth flight.

Pest	Southern Door	Central Door	Northern Door	Notes
Tarnished Plant Bug	Present	Present	Present	Light pressure continues
Codling Moth	Adults Caught	Adults Caught	Adults Caught	Flight continues *see caption below
Oriental Fruit Moth	Adults Caught	Adults Caught	Adults Caught	Flight Continues
Peach Tree Borer	Adults Caught	Adults Caught	Adults Caught

For more information visit the NEWA Codling Moth Model.

Disease	Southern Door	Central Door	Northern Door	Notes
Apple Scab	High Risk	Medium Risk	Medium Risk	Primary spore dispersal is complete. Check Apple Scab models on NEWA to time spray applications.
Fire Blight	Low Risk	Low Risk	Low Risk	Orchards should be monitored for shoot blight and strikes should be removed promptly, cutting 12-18 inches past the end of the canker.
Powdery Mildew	Medium to High Risk	Medium to High Risk	Medium to High Risk	More pressure with hot and humid weather in the forecast.

Cherries

Growth Stage: Fruit is mostly ripe throughout the county.
Seasonal Update: With continuing rain events in the forecast, a post harvest fungicide application will likely be needed. To check the rainfastness of your insecticide, visit this article from MSU and check your products accordingly.

Pest	Southern Door	Central Door	Northern Door	Notes
Spotted Wing Drosophila	High trap counts	High trap counts	High Trap Counts	Fruit is now highly vulnerable and protective sprays should be applied through harvest.
Cherry Fruit Fly	Adults Caught	Adults Caught	Adults Caught	Targeted sprays should go out 7-10 days after first catch followed by a second application 10-14 days later.

Disease	Southern Door	Central Door	Northern Door	Notes
Cherry Leaf Spot	High Risk	High Risk	High Risk	Risk increases with leaf area expansion and rain events
Powdery Mildew	Medium to High Risk	Medium to High Risk	Medium to High Risk	More pressure with hot and humid weather in the forecast.

Visit the Wisconet Pest & Disease Models page to check Cherry Leaf Spot for a weather station near you.

GRAPES

Growth Stage: E-L Growth Stage 32
Seasonal Update: Fungicides should be applied before berry touch to protect your fruit through harvest.

Pest	Station	Notes
Japanese Beetles	Large numbers caught	See this article from Christelle Guedot for information on managing Japanese Beetles.

Disease	Station	Notes
Grape Phomopsis	small amounts observed	Early season fungal control is critical to prevent diseases from reaching economically damaging levels.
Phylloxera	Galls observed in Itasca and Marquette varieties

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