Welcome back to our sixth report of 2025 Notes from the Field! As a reminder, this year’s Notes from the Field will follow Ben Kraus with Gwenyn Hill Farm (Waukesha). The goal of this newsletter is to hear from the grower’s perspective and foster connection between fruit growers. We’ll be focusing our discussions on phenology/fruit development and integrated pest management. This week, Ben is working on tackling continued plum curculio and codling moth pressure, as well as some increased disease pressure with recent precipitation.

I met with Ben on Monday, June 16th to check how things are shaking out after some recent precipitation and a string of warm, humid days. As a reminder, Gwenyn Hill has a 4-acre block of tree fruit and berries that sits along a north-facing slope, and ~150 table grape vines bordered by saskatoons and rhubarb across the road. Weather over the past two weeks (June 2 – June 16) has been moderate, with a few scattered precipitation events. According to NEWA, Gwenyn Hill had an average high temperature of 73.9℉, average low temperature of 53.2℉, and a total of 1.74” of precipitation (NEWA – Colgate, WI). Ben has a bit of a lighter apple crop this year, with king fruit at 20mm+, while grapes are into EL stage 18-23. Peaches are developing nicely despite the peach leaf curl. As for berries, elderberries are in full bloom and day neutral strawberries will have a second picking this week!

Note: Gwenyn Hill is impacted by the “lake effect” from Lake Michigan and is slightly behind in terms of phenology, compared to other southern WI locations.

This week I learned about a WI-based program called the “Organic Vegetable Farm Manager Apprenticeship Program” aimed to train the next generation of diversified organic farm managers. Gwenyn Hill is hosting two apprentices this year, mostly focused on diversified organic vegetables. However, the program is trialling work with a WI fruit farm and has a goal of expanding the program into fruit in the years to come – so stay tuned!

The Wisconsin Organic Vegetable Farm Manager Apprenticeship program trains and supports emerging organic vegetable growers. Apprentices work side by side with experienced farmers to develop their skills and learn the ins-and-outs of what it takes to run an organic vegetable farm – from seeding and transplanting to sales and marketing. In doing so, the program also connects established farms with dedicated longer-term employees who are motivated to learn. Registered with the state of Wisconsin, this competency-based apprenticeship spans two growing seasons and includes on-the-job training, classroom instruction, an hourly wage, and plenty of opportunities to connect with and learn from the broader farmer community. For more information, visit our website, or fill out the Apprentice General Interest Form / Farmer Educator General Interest Form. For questions, please contact program manager Sam Hsieh at sam@csacoalition.org.

Ben is working on finishing hand thinning the entire orchard, specifically removing fruit with plum curculio (PC) oviposition (egg laying) damage as well as fruit that have dropped to the orchard floor. Removing dropped fruit also helps prevent potential developing PC larvae from reaching reproductive maturity. Ben uses a bucket to gather fruit and offers it up as a tasty snack for the chickens! Ben is using a full cover of Surround (kaolin clay) to help deter PC, and Pyganic (pyrethrins) in hot spots where fresh injury continues to be observed. A reminder that plum curculio is a weevil that emerges right around petal fall, and remains active until ~308 degree-days (base 50℉) have accumulated from petal fall. Once 308 degree-days (base 50℉) have passed, typically PC cease movement into the orchard and no longer require control.

As for codling moth (CM), Ben just applied Cyd-X Virus (Cydia pomonella granulovirus) on June 16. His first codling moth trap capture was on May 28, and the area has just hit 250 degree-days (base 50℉), which is typically when larvae begin hatching out and search for fruit. Codling moth larvae are also internal fruit feeders and can lead to significant economic damage. Removing fallen fruit also helps prevent potential developing CM larvae from reaching reproductive maturity. As a reminder, a biofix occurs when an influx of ~5+ moths are cumulatively captured across traps, or captured on consecutive days (sustained capture).

Note: Several factors determine the threshold for biofix, including size and elevation within the orchard, type of pheromone lure used, and if mating disruption is used.

Precipitation in the last two weeks in combination with the warmer temperatures and humidity has pushed disease pressure along. This week we observed several diseases including: brown rot in cherries, apple scab and cedar apple rust in apples, peach leaf curl in peaches and black rot in grapes. Ben is keeping the orchard covered with Potassium Bicarbonate and Serenade (QST 713 strain of Bacillus subtilis) to help limit spread of these diseases.

That’s all for this week’s Notes from the Field. Good luck and best wishes to all WI Fruit Growers over the next two weeks!

This article series is NOT intended to be prescriptive for other orchards. It is simply an opportunity for our readership to hear from other growers about their experiences growing fruit crops in Wisconsin. 

Growing the same crop does not always justify the same practices. Management decisions at your farm should be tailored to your operation and consider location, regional climate, disease and pest history of your vineyard, and your varieties. 

The mention of a product is NOT an endorsement. Always follow the instructions on product labels and consult weather stations (ex. NEWA) in your area for current weather forecast and disease and pest prediction models.

This article was posted in Notes from the Field and tagged Ben Kraus, Josie Dillon, Notes from the Field.