Fruit Update - April 16, 2026

 Article written by Madeline Wimmer, UMN Extension Fruit Production Educator

• Apples
• Growth stage update: Green tip - ½ inch green, except for Zestar!®
• Apple scab
• NEWA for apple management
• Grapes
• Growth stage update: Some varieties at early bud swell and the sap is flowing
• Delayed bud-break and double pruning
• Honeyberries
• Growth stage update: Leaves out and floral buds developing
• Fruit variety highlight
• Moongold (Apricot) in bloom

Spring is coming along at full speed as woody plants seemed to accelerate in growth, Magnolia’s bloomed, and landscape turf greened up after the rain passed through Southeast Minnesota this past week. We’ve had a number of days passing 70°F, although this weekend will bring some temperature dips around freezing. With that in mind, let’s take a look at some fruit crop growth stages and management recommendations for this week!

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 form. If you have a question you want addressed in a future update article, you can include that in your report.

Apples

Growth stage update: Green Tip - 1/2 inch Green, except for Zestar!®

Images: A range of growth stages were exhibited by apple varieties First Kiss (upper left photo) emerging out of green tip, McIntosh (upper right photo) and Honeycrisp (lower left photo) at ½ inch green, and Zestar! (lower right photo) at tight cluster. This is typical for Zestar! to be ahead in development compared to other apple varieties. Photos taken at Sekapp Orchard in Rochester, MN, April 14, 2026. 

Within a week, apple varieties passed from silver tip, through green tip, and are now showing buds in ½ inch green, with the exception of the variety Zestar!, which was in green tip last week and is now approaching tight cluster. If you’re new to learning about apple growth stages, we recommend checking out this chart from Michigan State University. As was mentioned in last week’s update, learning growth stages is important to understanding the varieties you grow and their management needs.

Apple scab 

When 50% of apple buds are in the green tip stage, this date can be recorded and used as a biological marker to help estimate when all overwintering primary spores (i.e., ascospores) have been released from fruiting bodies of the apple scab pathogen, Venturia inaequalis. 

For more information on apple scab and its management, check out this week’s UMN Fruit and Veg News article:

Apple Scab: About and significance of early season management

NEWA for apple management

One software program that has been used by the UMN Horticultural Research Station and is being further adopted by more Minnesota apple growers is Cornell’s Network for Environmental and Weather Applications (NEWA) apple scab program. NEWA works by connecting to a weather station and automatically downloading data about rainfall, leaf wetness, temperature, relative humidity, and other aspects. NEWA currently works with two different weather station brands: Onset Data Loggers and Kestrelmet. 

NEWA can be used to track both apple-relevant diseases (apple scab, fire blight, sooty blotch and flyspeck), insect pests (apple maggot, codling moth, obliquebanded leafroller, oriental fruit moth, plum curculio. San Jose scale, spotted tentiform leafminer), as well as blossom and fruit thinning (apple carbohydrate thinning model, pollen tube growth model) and irrigation. Click here to see the list of options. 

Yesterday, I met with the Minnesota Apple Growers Association to discuss ways of supporting growers who are new to using weather stations and using NEWA. If this is something of interest to you, please reach out to me. 

Grapes

Growth stage: Some varieties at early bud swell and the sap is flowing

Sap flow

Image: A recently cut cordon shows a droplet of sap that was actively dripping from a cut cane below the wound point, while the sap on the larger wound has begun to gum up. Photo taken in Rochester, MN, at Firefly Berry Farm, April 16, 2026.  

This sap is flowing in grapes in Southeastern Minnesota and at the Horticultural Research Center (HRC). Sap flow is a sign that grapevines are transitioning from dormancy to active growth. This happens when the soils warm up and roots actively release stored starch and proteins into the vascular system (xylem) as simpler sugars and amino acids. This process leads to water going into the roots, which leads to pressure in the xylem and leads to these nutrients being pushed toward the shoot tips. This means that the sap is full of nutrients helpful for budbreak! If you see sap flowing from the ends of canes or older wood, know that this is not harmful for the plant. 

Resources cited: Grapes 101: Grapevine Roots (Cornell CALS)

Bud growth stages

Images: Upper photos from left to right: Frontenac, La Crescent, and Marquette are nearly dormant or just entering budswell at the UMN Horticultural Research Center (HRC). Lower photos from left to right: Edelweiss, Vitis amurensis, and Vitis riparia showing different rates of budswell and ahead in development. Photos taken by John Thull, April 16, 2026. 

Grape cultivated varieties (cultivars) observed this week are in a range of growth stages from basically dormant (winter bud) to early bud swell (bud scales opening). I checked on a small vineyard in Rochester, MN, this morning, where Concord is grown and, while the sap was flowing, most buds were basically dormant. At the UMN HRC, some varieties like La Crescent and Frontenac were barely approaching budswell, with Marquette even more behind. A number of other varieties, including Edelweiss as well as some of the native grapevines grown for breeding like Vitis riparia and Vitis amurensis, were at early to mid-budswell. 

Delayed bud-break and double pruning

Delayed budswell can be an advantage to cold climate grape production, as late-season frost can be an issue in some regions, especially when vines are planted in low spots where cold air settles. Because grapevine buds begin to break at the tips of canes (one-year-old shoots), smaller vineyards, or vineyards that use a tractor-attached barrel pruner, can actually utilize this to their advantage by long-pruning canes to 8 buds/nodes and coming back at a later date to reduce the bud count to 2-4 buds. This is sometimes referred to as double pruning and a paper was recently published (2022) reviewing the process, where authors suggested it can delay budbreak from 15-20 days for vines that were studied. This can have a minor effect on yield, estimated to be up to 17%, but as an alternative to losing more than that from cold damage, it might be beneficial for some vineyards to consider.  

The Fruit Update series will continue to track grapevine growth stages using the E-L Chart. Similar to other fruit crops, being familiar with growth stages and plant phenology can help you get to know differences between cultivars and know the best practices for pest and disease management for your vines. 

Resources cited: Facing Spring Frost Damage in Grapevine: Recent Developments and the Role of Delayed Winter Pruning – A Review (Poni, S., et. al.; American Journal of Enology and Viticulture)

Honeyberries

Growth stage update: Leaves out with floral buds developing

Image: Honeyberry shrubs in Southeastern Minnesota are leafing out with buds developing toward bloom. 

Honeyberries, or haskap, are an early-blooming shrub in the honeysuckle family. Honeyberries are highly cold tolerant, produce a blue fruit (technically two-fruits encapsulated in a thin skin for each syncarpous berry), and do not have the acidic soil requirements like blueberries do. There are early and late blooming varieties, and, while honeyberries require cross pollination similar to apples, they are only pollen-compatible with varieties that are genetically distinct, a phenomenon known as cross-incompatibility based on genetic relatedness. 

If you are interested in learning more about honeyberries, check out an article written about our Upper Midwest Honeyberry Academy we hosted last summer in Stillwater, MN, at George Terway’s farm. 

Article link: First Upper Midwest Honeyberry Academy hosted in Stillwater, MN

Fruit variety highlight

Moongold (Apricot) in bloom

Image: The apricot variety Moongold is quickly approaching full bloom. Photo taken by Kate Scapanski at the UMN HRC on April 16, 2026. 

The University of Minnesota’s MN Hardy website lists UMN bred apricots as, “fine, ornamental small trees with an early spring bloom and bright orange-yellow fall color,” and based on this photo, you can see why it’s not listed as a fruit crop for production purposes. 

This is Moongold, one of two apricots bred through the UMN Fruit Breeding program, with its cross-pollinator counterpart being Sungold (both released in 1960). It’s nearing full-bloom in the middle of April during a week where most pollinators are not active and we’re about to dip into mildly-freezing temperatures again. If fruit set occurs, it will ripen in late July, while Sungold tends to ripen closer to early August.

Stone fruit crops like Apricots and Peaches can be a challenging crop to get consistent yields without interventions like high tunnel production with double coverage in the winter. Dan Shield of Stone Creek Farm is one Minnesota grower who does grow a number of peaches, as well as apricots and nectarines under sheltered production, and has taken years to learn about and alter his system to get healthy production. We’ll hopefully cover more about stone fruits for the purpose of communal interest again this growing season, so stay tuned. 

Thank you to our farm and ag professional partners for contributions to the UMN Fruit Update series. Non-credited photos in this article were taken by Madeline Wimmer.