Article written by Madeline Wimmer, UMN Extension Fruit Production Educator.
Apples
Photo: Apple maggot (Rhagoletis pomonella) on Dolgo crab apple
Article: Cider apple production
Grapes
Growth stage update: Early- to mid-veraison
Bird management in vineyards
Converting lyre to VSP
Article: Identifying herbicide damage in grapes
Apples
Photo: Apple maggot (Rhagoletis pomonella) on Dolgo crab apple
Image: An apple maggot adult fly is on a Dolgo crab apple variety in Schafer, Minnesota. Photo by Madeline Wimmer.
If you’re new to trapping apple maggot flies, it’s important to know how to identify them to inform your management program. Adults can be distinguished from other adult flies by their black bodies and ‘F’-shaped pattern on their wings.
To learn more about apple maggot management, check out an article posted earlier this year in the UMN Fruit and Veg Newsletter, “Preparing for apple maggot management in 2026 (organic and conventional practices),” and refer to resources like Cornell’s Network for Environment and Weather Applications (NEWA), and the Midwest Fruit Pest Management Guide.
Article: Cider apple production
Images: A few apple cultivars used for cider production at Keepsake Cidery’s orchard, including Centennial Crabapple (upper left), Ellis Bitter (upper right), and Foxwhelp (lower left), located near Northfield, Minnesota (Zone 5a).
Cider apple production can utilize apples that are used for fresh eating, especially when the goal is to produce something bright, or tart. In order to get more classic ciders with complex flavors and mouthfeel, however, growers often look to apples that were traditionally bred for cider, which can have a higher tannin content and more complex flavors. Beyond cultivar choice, production methods can impact the final product, just like with wine. Continue reading more about this topic in this week’s article:
Article: Minnesota hard cider apple production and cultivar selection
Grapes
Growth stage update: Early- to mid-veraison
Images: Three grape cultivars in veraison: Marquette (red), Prairie Star (white), and Frontenac Gris (pink/grey).
At Salem Glen Winery’s vineyard, located just outside of Rochester, Minnesota, many of the varieties are beginning to enter veraison, with Marquette, Frontenac, and Frontenac Gris ahead of the 10+ other cultivars they grow.
Shown in the above photo is also Prairie Star, distinguished by its tight, long cluster with prominent calyces. Prairie Star is often recommended as a pollinizer, or a pollen source to be planted close by St. Pepin—a grape cultivar that only produces female flowers. St. Pepin is often more desirable for winemaking, while Prairie Star can balance out white blends.
Veraison is an important marker in grape development as it marks the time when grapes begin to soften and accumulating sugars into their fruit. It will still be a number of weeks before harvesting most of these varieties, and during that time period, the berry acidity will continue to lower, while flavor compounds also build within the fruit.
Bird management in vineyards
Image: Plastic mesh netting can be stored as a spool. In the vineyard in this photo, the netting was clipped to PVC tubing and rolled up using either a forklift or attached rebar and a handmade crank fitted to the PVC tube. Photo taken at Cambridge Winery located in Cambridge, Wisconsin (Zone 5b).
If you’re seeing veraison beginning in your vineyard, that’s also a good time to plan your vineyard netting, or bird management strategy. If you’re itching to get started and learn more, check out this week’s article:
Article: Bird management in vineyards
Grower highlight: Converting lyre training system and trellis to VSP
Images: The lyre trellis was originally designed to create a split, double-canopy with upward trained shoots.
One way to address high vigor vineyard sites is to make a double-canopy system that will produce a larger canopy and more fruit. This can be done with a two-dimensional trellis, as in the case for the Scott-Henry system, or three-dimensional trellis systems, including the Geneva Double Curtain (GDC) and Lyre training systems.
GDC is seen more often in the Midwest, due to its downward shoot training system, while the Lyre trellis originated in France for Vitis vinifera grapevines with the additional intention to increase sunlight and air movement into the canopies.
At Four Daughters, some rows of Lyre were originally installed with the vineyard, but they have recently transitioned away from the double-canopy system. Hannah Hanlon, their vineyard manager, had experienced frustration with the wider rows and trying to manage the canopies with the given space.
Image: After the Lyre endposts are removed, a simple endpost remains with markings to show where the Lyre pallets were originally installed.
During the past couple of years, she has worked to convert their Lyre rows into Vertical Shoot Positioning (VSP) for uniformity and ease. The process involves removal of one side of the divided canopy and sometimes involves retraining cordons (for two trunk systems) onto the other side.
Hannah mentioned she still appreciates VSP as an alternative to High Wire Cordon (HWC) because it makes pruning and harvesting easier since there is less of a reach. While HWC canopies are trained to higher heights, which can have the benefit of escaping spring frosts, there seems to always be a tradeoff among training systems, and worker comfort is important.
Article: Identifying herbicide damage in grapes
Images: Herbicide damage on grape leaves can show a number of different symptoms, depending on the damage. The photos above are showing what is known as “shoe-stringing” where the leaves look like a thread has been pulled, leading to a tight, bunching appearance.
Herbicide drift can happen on-site from misapplications, or off-site, due to applications on nearby farms, county ditches, or other managed lands. Grapes are sensitive to herbicide drift, and especially so to 2,4-D and dicamba. This week's article goes into drift damage identification, some steps to try to prevent drift, and how to report drift when needed.
Article: Herbicide damage identification: Vineyards
Thank you to our farm and ag professional partners for contributions to the UMN Fruit Update series. Non-credited photos in this article were either taken by Madeline Wimmer or within the UMN Extension system.
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