Fruit Update - April 23, 2026

Article written by Madeline Wimmer, UMN Extension Fruit Production Educator. 

• Apples
• Growth and pest management updates - Pink: early to late
• Bloom compatibility- Considerations for Minnesota with notes from David Bedford, UMN Apple Breeder
• Grapes
• Growth stage and pest management updates - Woolly bud (bud swell); (grape flea beetle highlight)
• Aronia 
• Growth stage and variety highlights
• UMN Extension Fruit Crop Reporting Tool

Apples

Growth updates - Pink (early to late)

Images: Top (from left to right): Gala, First Kiss, and McIntosh; Bottom (from left to right) Zestar! and Honeycrisp showing various stages of pink, the growth stage before king bloom, where the first flower opens. Photos taken at Sekapp Orchard in Rochester, MN, April 23, 2026. 

We’ve had a mixture of cooler nights and more warm-ups the past week in Southeastern Minnesota, and the apple varieties I’ve been following at Sekapp Orchard have been steadily developing toward pink, with Zestar! in the lead. Honeycrisp tends to bloom later in general and is showing more clusters in the tight cluster growth stage, with some starting to show a hint of pink (see photo above). 

The pink phase lines up with critical timing for controlling apple scab, one of the most important diseases to manage in Minnesota. I often follow ascospore discharge and infection predictions using the Cornell Network for Environmental and Weather Applications (NEWA) at the UMN Horticultural Research Station near Chaska, MN. This year, they reached green tip for many of their varieties around April 14th. 

Based on weather conditions and degree day accumulations, NEWA predicts that around 12% of ascospores (primary spores) have been discharged from overwintering fruiting bodies today, and with the predicted rain events between later this evening through Monday, it’s forecasted that 26% will have discharged by Tuesday of next week (April 28th). 

After 100% discharge has occurred, and as long as plants have been protected to prevent infections, the infection likelihood from conidia (secondary spores) will be fairly low. This is why early disease management programs can be so effective for mitigating season-long apple scab infections. 

For other notes on apple disease and insect pest management during this growth stage, look to page 19 in the Midwest Fruit Pest Management Guide, available for free as a pdf download on the Purdue Extension website.

Bloom compatibility- Considerations for Minnesota with notes from David Bedford, UMN Apple Breeder

Apples require cross pollination with other varieties in order to have successful pollination. Both crab apples and edible apple varieties work well to provide pollen as a pollinizer (a pollen source). The one consideration to think about for tree compatibility for pollination is bloom time. Most commercial orchards grow enough variation in varieties where bloom overlap will occur, but if you’re just getting started, this is something to keep in mind. 

As mentioned in the above section, some varieties like Honeycrisp and Chestnut Crab tend to bloom very late, while Zestar! is an example of a variety that blooms earlier. If you’re exploring varieties to balance out bloom timing in your orchard for future years, you can refer to an apple bloom chart like this one located on the Food Forest Nursery website. It’s comprehensive and includes a number of varieties that can be successfully grown in the Upper Midwest. 

When I reached out to David Bedford, UMN Apple Breeder and known for his work on breeding Honeycrisp, he mentioned that UMN hasn’t done a lot of work to create bloom charts because most Minnesota orchards have very good bloom overlap with a majority of UMN varieties. This is partly due to our historically colder springs, which leads to one of the latest bloom periods in the US. He refers to this as a compressed bloom period where the majority of varieties have overlap in when they bloom. This also decreases the chance for frost susceptibility to blossoms. David also mentioned, in regards to using flowering crabs as a pollinizer, they tend to have a much wider range of bloom dates between varieties than UMN varieties do, which means timing can be important when choosing a flowering crab. 

Grapes

Growth stage updates - Woolly bud (bud swell); grape flea beetle highlight

Images: Itasca (top left), Louise Swenson (lower left), and La Crosse (right) all in the woolly bud phase of development. Photos taken at Salem Glen Winery in Rochester, MN, April 23, 2026. 

Grape bud development is around the phase known as “woolly bud” (bud swell stage 3) in the E-L Growth Stage Guide. Grape buds are still quite hardy at this phase, the exact critical temperature varies depending on the variety along with other environmental factors and how long the cold prevails, but they can start to show damage when temperatures dip into the lower 20s. 

Pest management for grapes starts on page 134 of the Midwest Fruit Pest Management Guide, with notes about the delayed dormant to bud swell pest management on page 136. In general, applications of dormant oils and lime sulfur should be avoided at this time. This stage also is a marker to start scouting for grape flea beetles, especially if you have had issues with them in the past. 

Images: Grape flea beetles (Altica spp.) can lay their eggs on developing buds and bark, or on the underside of grapevine leaves as seen in the leftmost picture here. As adults emerge from winter, they feed on grape buds and mate. Damage to developing buds can interrupt shoot growth. Photos credited to T.L. Galvan and E.C. Burkness.

Grape flea beetles (Altica spp.) get their name from their ability to jump similar to a flea when surprised. There are two main species, which vary based on where they lay their eggs (either on developing buds and bark, or on the underside of grape leaves). Their life cycles are similar in that they overwinter in various semi-sheltered environments, like woodlands, as adults. 

Adults go on to feed on developing grapevine buds as they begin to swell in the spring. Buds are most vulnerable between the bud swell stage until the first leaf separates from the shoot tip. Damage can look like a small hole in a bud, and this can interrupt shoot growth and lead to a reduction in yield. After feeding and mating, adult females lay eggs that eventually hatch into larvae, which can then feed on grape leaves, although the impact is minimal compared to bud damage in the spring. 

Aronia berries

Growth stage and variety highlights

Images: Both Autumn magic (left) and Viking (right) are considered aronia berries as a common name, and can be grown in the Upper Midwest with little input. Photos taken at Salem Glen in Rochester, MN, April 23, 2026. 

Aronia berries (also known as chokeberries, but not chokecherries) are a distinct fruit crop high in a type of polyphenols known as tannins, which leads to their astringency and why I sometimes refer to them as the red wine of berries. Aronia can typically survive in USDA Hardiness Zones as cold as Zone 3, making them suitable for the Upper Midwest. The species Aronia melanocarpa (i.e., black chokeberry) is commonly used in landscaping, with varieties like Autumn Magic and Morton. 

The cultivar Viking is probably the most popular aronia berry cultivated in the Upper Midwest, largely because of its reputation for having larger fruits, lower astringency, and its tendency to not spread by vegetative growth from rhizomes. Viking was originally developed by a plant breeder in Russia, Ivan V. Michurian, and, while its genetic background is still debated by some, it is possible that European mountain ash (Sorbus aucuparia) is in its heritage. Nero is a second well-known cultivated variety that came from these breeding efforts.

While the variety Autumn Magic is less likely to be used as a food crop, due to its higher tannin and low juice content, Salem Glen Winery in Rochester, MN, has preferred to incorporate it into one of the wines they produce and prefers it over Viking. 

Both varieties have floral buds out and will begin to bloom sometime in the near future. Aronia are self-compatible. Similar to other fruit crops, however, having multiple varieties can improve fruit set.   

Sources: 

Brand, M.H. 2013. Breeding better aronia plants. https://ena.ipps.org/uploads/docs/63_059.pdf

Leonard, P.J. 2011. Aronia mitschurinii: Solving a horticultural Enigma. University of Connecticut. Master’s Theses. pp 183.

UMN Extension Fruit Crop Reporting Tool

Interested in sharing anything about the fruit crops on your farm? Feel free to share observations about diseases, pest management, or other production aspects using our new UMN Extension Fruit Crop Observation Report tool. If you have a question you want addressed in a future update article, you can include that in your report.

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.