By Becky Wiepz and Dan Kielar
Station Updates
- Bloom is progressing throughout the county with most cherries and apples moving from full bloom to petal fall
- Mulching of orchards and vineyards is in progress on the Station
UW Madison/Extension Updates
- Thinning Decisions and Weather Outlook for Wisconsin Apple Growers
- Wisconsin Orchard Update: Fire Blight Management
- Event: Mount Horeb, WI – Organic Orchard Floor Management Field Day – June 11, 2025
- Event: Stillwater, MN – Upper Midwest Honeyberry Academy – July 1, 2025
Historic Growing Degree Day Comparison
| Date 5/28 | 2021 | 2022 | 2023 | 2024 | 2025 | 20-year avg. |
| Base 50 | 277 | 223 | 283.5 | 352.5 | 232.5 | 271 |
Recent Weather at Peninsular Ag Research Station
| Date | Max Temp(℉) | Min Temp(℉) | Max Wind Gust(mph) | Daily Rain Total(in) |
|---|---|---|---|---|
| 5/22 | 55.6 | 42.4 | 29.5 | 0.01 |
| 5/23 | 58.3 | 42.6 | 21.0 | 0.0 |
| 5/24 | 59.4 | 42.4 | 22.1 | 0.0 |
| 5/25 | 62.1 | 37.2 | 13.4 | 0.0 |
| 5/26 | 68.5 | 41.7 | 11.6 | 0.0 |
| 5/27 | 70.0 | 50.9 | 13.9 | 0.0 |
| 5/28 | 66.9 | 50.5 | 11.6 | 0.0 |
If you’d like to see weather data for your area, visit https://wisconet.wisc.edu/
Apples
Growth Stage: Full Bloom to Petal Fall, depending on variety
Seasonal Update: Avoid Insecticide Application when blooms are open to protect pollinators. Lime sulfur sprays need to be applied during bloom to impact crop load. Visit the Pollen Tube Growth Model on NEWA to accurately plan blossom thinning sprays.
| Pest | Southern Door | Central Door | Northern Door | Notes |
|---|---|---|---|---|
| Green Fruit Worm | End of Flight | |||
| Tarnished Plant Bug | None Caught | None Caught | Appears to be a break in movement | |
| Spotted Tentiform Leafminer | Present | Present | Present | Flight continues |
| Codling Moth | No Catch | 1 Catch | 1 Catch | Flight started *see caption below |
| Blossom Feeders/Lepidoptera | Low Pressure | Low Pressure | Low Pressure | |
| Oriental Fruit Moth | First Catch | First Catch | No Catch | Start of Flight |
| Disease | Southern Door | Central Door | Northern Door | Notes |
|---|---|---|---|---|
| Apple Scab | Medium Risk | Medium Risk | Low Risk | Increased risk with increased leaf surface and rain. Check Apple Scab models on NEWA to time spray applications. |
| Fire Blight | Low Risk | Low Risk | Low Risk | Warm temperatures and rain can lead to growth and spread of fireblight bacteria. When blossoms are open, protective sprays should be used. |
Cherries
Growth Stage: Petal Fall
Seasonal Update: Fungicide should be applied before rain events now that bract leaves are open.
| Pest | Southern Door | Central Door | Northern Door | Notes |
|---|---|---|---|---|
| Plum Curculio | Fruit is not at risk of PC damage until after shuck split |
| Disease | Southern Door | Central Door | Northern Door | Notes |
|---|---|---|---|---|
| Cherry Leaf Spot | Low Risk | Low Risk | Low Risk | Risk increases with leaf area expansion and rain events |
GRAPES
Growth Stage: 4″-8″ shoots
Seasonal Update: As humidity and rain increase, it is important to scout for fungal pathogens and spray fungicide before rain events.
| Pest | Southern Door | Central Door | Northern Door | Notes |
|---|---|---|---|---|
| Flea Beetles | Low risk | Low risk | Low risk | Increasing risk as temperatures climb |
| Disease | Southern Door | Central Door | Northern Door | Notes |
|---|---|---|---|---|