August 7, 2025

---

By Becky Wiepz and Dan Kielar

Alert! High Spotted Wing Drosophila trap counts

Station Updates

• Cherry harvest is complete on the Station!

UW Madison/Extension Updates

• Summer Pruning Apples: A Smart Strategy for Better Fruit and Easier Harvest
• Wisconsin Orchard Update: Bitter Rot and SBFS Management Reminders
• Wisconsin Fruit Crop Scouting Report: July 28, 2025
• Veraison Disease Management Considerations for Wisconsin Vineyards

---

Historic Growing Degree Day Comparison

Date 8/6	2021	2022	2023	2024	2025	20-year avg.
Base 50	1488	1378.5	1440	1498.5	1425	1443

Recent Weather at Peninsular Ag Research Station

Date	Max Temp(℉)	Min Temp(℉)	Max Wind Gust(mph)	Daily Rain Total(in)
7/30	74.1	61.2	10.5	0.0
7/31	72.7	53.6	19.5	0.0
8/1	73.6	50.2	11.6	0.0
8/2	78.8	58.6	8.9	0.0
8/3	78.4	59.4	10.1	0.0
8/4	78.1	55.4	8.9	0.0
8/5	78.6	60.4	11.2	0.0
8/6	79.7	63.7	12.8	0.0

Apples

Growth Stage: Fruit continues to size and early varieties are starting to blush.
Seasonal Update: 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
Apple Maggot	Adults Caught	First Catch	None Caught

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 almost completely harvested throughout the county.
Seasonal Update: With continuing rain events in the forecast, a post harvest fungicide application will likely be needed in some blocks. Check Pressure in your orchard to plan your applications.

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. NO INSECTICIDE SHOULD BE APPLIED AFTER 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.

GRAPES

Growth Stage: E-L Growth Stage 33
Seasonal Update: Fungicides should be applied before bunch closure 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.
Wasps	None observed	Wasp populations will rise once fruit enters veraison.

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

Additional Resources

• Rainfast Characteristics of insecticides on fruit
• Chlorpyrifos (lorsban) is not allowed on any fruit crops in Wisconsin
• Take Steps To Ensure That You’re Complying With the EPA Herbicide Strategy To Protect Threatened and Endangered Species