Article written by Madeline Wimmer, UMN Extension Educator, Fruit Production
All fruit
End-of-season newsletter survey and letter from the Educator
Apples
Did your orchard experience hail this year? Hail netting has its advantages.
Cultural management: Encouraging leaf decomposition for managing apple scab
Grapes
Article: Late season, occasional insect pests in Minnesota vineyards
Honeyberries
Site specific highlight: Fall planting
June-bearing strawberries
Article: Manage next year’s strawberry weeds this fall
All fruit
End-of-season newsletter survey
A big thank you to those who have taken the time to share their feedback on our newsletter to shape our content for the 2026 growing season! There’s still time to take the survey below.
If you haven’t had a chance to check out the end-of-season letter from the Educator, you can access it through this link to last week’s Fruit update:
A note of thanks from the Educator
End-of-season newsletter survey (Share your thoughts on the newsletter!)
Apples
Did your orchard experience hail this year? Hail netting has its advantages.
Images: 1) Golf ball sized hail that occurred shortly after a harvest event near Madison, WI (Zone 5b) in 2016. 2) Draped hail netting installed over central leader and (3) high-density apple trees at Pine Tree Apple Orchards, located near White Bear Lake, MN (Zone 5a).
This summer, a number of Minnesota and Upper Midwest apple growers reported impact from hail storms. While hailstorms are an extreme weather that may occur infrequently, the damage can be devastating depending on when and which growth stage it happens. This can lead to disease issues (refer to our article on Fire Blight from August) and impact fruit marketability.
Hail can range in severity and size, from less than pea-sized to as large as golf balls. Insurance options exist to cover hail damage, but the cost-to-recovery ratio may not always be adequate to make up for damage.
Images: Examples of hail netting installed as overhead, which only covers the tops of the orchard block, making it effective against hail damage, although it cannot be used to exclude insect pests.
That’s where hail netting comes in. Hail netting is a physical way to exclude hail and mitigate the damage. Hail netting has a finer mesh (typically 3mm by 1.5mm) than netting used to protect against bird damage.
It can be installed in two different ways:
Overhead netting: installed over an orchard block and held up by posts or other structures.
Draped netting: provides full coverage over one or multiple free-standing trees, or a trellised row of high-density apples.
Both provide barriers where hailstones bounce off from the netting and fall onto the ground. However, only draped netting can be used as a method to exclude insect pests like codling moth and apple maggot.
Installation for either method takes a good amount of strategy and consideration to things like fastening it to end row posts or stakes. Overhead netting benefits from tying together individual pieces of netting, while simultaneously providing gaps where hail can fall through, rather than pooling and weighing down on specific areas of the netting.
Draped netting will need to be fastened around all sides of the tree canopy when used for insect exclusion, including the bottoms of the net. Additionally, some growers install structures like cross bars, or horns, that keep the netting from bunching shoots into an upright position.
To learn more about overhead and draped hail netting, check out the University of Minnesota’s links below.
Hail netting for apple orchards (webpage)
Hail netting in apple orchards (short video)
Climate change and fruit crops: Excluding the elements (9 minute video)
Cultural management: Encouraging leaf decomposition for managing apple scab
Much effort is put toward managing apple scab primary infections during the spring when overwintering fruiting bodies release spores during rain events, especially when temperatures are warm and in an optimal range.
As long as these initial spores are prevented from creating new asexual spores on leaves and fruits, the amount of inoculum, or overwintering spores present by the end of the year is greatly reduced. For growers who do experience secondary infections, however, encouraging leaf decomposition during the fall can be a helpful practice to decrease the amount of overwintering fruiting bodies and spores that are released during the following spring.
Leaf decomposition occurs when the environment weathers on infected leaves and fruits and microorganisms contribute by consuming and breaking down plant material and fruiting bodies along with it. This process can be encouraged by stimulating microbes through spray applications of urea at a 5% solution (46-0-0), which comes out to 42 pounds of urea in 100 gallons of water (1).
The other way leaf decomposition is encouraged is by increasing the total surface area of the leaf litter by mowing the leaves. This is sometimes easier said than done, especially for larger orchards where leaves can get stuck underneath trees. For instance, Ben Fontana, orchard manager at Apple Jack Orchards, has taken the time to improve this method by using a leaf blower to force leaves into the aisles between tree rows. This works best when the direction of the wind can be used to their advantage by blowing the leaves with the wind.
A combination of both methods, encouraging microbial growth and making it easier for them to consume the leaf litter, can work well for orchards that have the time and resources to be more thorough.
Resources:
Peter, Kari A. Apple diseases - Apple scab. PennState Extension. 2023.
Grapes
Article: Late season, occasional insect pests in Minnesota vineyards
Images: The multicolored asian lady beetle (left; Harmonia axyridis), social wasps like yellow jackets (middle; Vespula and Dolichovespula spp.), and common fruit flies (Drosophila menogaster) are all insects that can lead to issues with grapes as harvest approaches.
There are a few insect pests that can occasionally cause issues in vineyards in Minnesota, especially when fruits are damaged or experience splitting. This includes insects like the multicolored Asian lady beetle, social wasps, and fruit flies, which cause a variety of issues for harvest from potential wine taint, or further damage to fruits, or even give way to disease problems like sour rot.
Check out this week’s article to learn more about these pests, and how to monitor and manage them around harvest this year.
Article: Occasional insect pests that attack damaged berries in Minnesota vineyards
Honeyberries
Image: Phil Stowe of Walking Plants Orchard uses an auger to guide his planting of 700 new honeyberry transplants on site.
Site specific highlight: Fall planting at Walking Plants Orchard
Spring is generally a good time to plant fruit crops in Minnesota, where bareroot plants can be planted as soon as the soil is workable, while potted plants that are actively growing are best planted after the risk of frost has passed. As long as plants are well cared for by managing ground competition with other plants (i.e., weeds) while also receiving enough irrigation and nutrition, most fruit crops also do well when planted early in the summer. However, planting fruit crops in the fall can also work out, especially during years with high summer temperatures and drought-like conditions that can lead to plant stress. It’s not that cooler temperatures stimulate root growth as much as very hot temperatures can inhibit growth.
In Minnesota, where milder fall temperatures can be limited to a shorter period than more southern states, planting earlier in the fall often gives plants more time to establish as dormancy sets in and before the first frost events occur.
This week, I spoke with Phil Stowe of Walking Plants Orchard who grows honeyberries and is continuing to install 700 more University of Saskatchewan varietal transplants this fall at his farm. Phil has found that both fall and spring plantings work well for honeyberries, though during years when nursery stock arrived later in the season (June), he often finds himself busy with a number of other tasks and prefers to care for them in a concentrated area where they are closer together, before he can make time to prepare his fields to plant the honeyberries. This also works well because Phil does most of his work on his own and grows a crop like honeyberries, which are harvested earlier in the summer.
Transplants can generally be planted by trenching out a row in the soil, or digging holes by hand or using an augering tool, in which all methods have their advantages and challenges. Phil is using an auger attachment on a skid-steer loader for this new planting as a means of creating holes, which also clearly marks the planting location, while maintaining an idea of the row and aisle lengths.
At some point, after he has finished planting, Phil plans to install landscape fabric as a means of preventing competition with weeds. Overall, when it comes to winter survival, previous plantings have fared well over the winter since honeyberries are well adapted to cold climates and are very cold hardy.
June-bearing strawberries
Article: Manage next year’s strawberry weeds this fall
Weed management is often a huge challenge for June-bearing strawberries grown in matted rows in the Upper Midwest, taking more time each year than any other tasks. This week’s article focuses on management timing and herbicide strategies for strawberry beds that can be done in the fall to reduce the number of weeds in a strawberry bed the next year.
Article: Manage next year's strawberry weeds this fall
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.
This article may be shared for educational purposes with attribution to the University of Minnesota Extension. For other uses, please contact UMN Extension for permission.
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