Michigan State University Extension

Blueberry Newsletter - Blueberry Bites

Welcome to the first edition of

MSUE Blueberry Bites!

For the remainder of the growing season make sure and check your inbox weekly for bite-sized updates from the blueberry experts at Michigan State University.

-Michigan State University Extension Blueberry Team

View From The Field

Bluejay - Paw Paw

Bluecrop - Paw Paw

Bluecrop - Fennville

Pest Update: Insects

For pest insects, it is time to get monitoring programs rolling. Some sporadic leafroller feeding was reported where larvae were eating the blossoms, but this was not at high enough levels to warrant treatment. If cherry or cranberry fruitworms have been an issue for your farm, get the monitoring traps up soon so you can set an accurate biofix for later treatments to protect berries. If gall wasp is in some of your fields, pruning and immediate post-bloom treatments are your best options. Check THIS article and watch MSU Extension News for an upcoming article next week summarizing gall wasp controls.  

Pollination Update

The warm weather has been good for early bloom development, and we are seeing a progression of opening blooms in the earlier cultivars through this week. Beekeepers are delivering honey bee colonies to fields, and with peak temperatures in the 70s this week there should be rapid development of bloom and good conditions for pollination. Consider pesticide risks to pollinators if selecting disease control sprays, and use this GUIDE. If you’re interested in grading your honey bee colony strength, our Bees & Berries project just released a new video on this topic.

Grading Colonies for Blueberry Pollination
Minimizing Pesticide Risk to Bees in Fruit Crops
May 17 Pollination Workshop  Van Buren County
Percent Bloom - Grand Junction

Pollinator Workshop - May 17 & June 1

The program will include a description of pollination practices at the host farms and results from recent research at these locations. Presentations will be by experts from the MSU Department of Entomology including Meghan Milbrath (honey bees) and Rufus Isaacs (blueberry pollination). The events will include a mix of hands-on demonstrations of sampling for colony strength, bee activity levels in the crop field, and pollination success. There are no RUP credits for this program. Sign up for May 17's workshop here.

Pathogen Update: Mummy Berry

Blueberry growers should be on the lookout for mummy berry apothecia and be applying preventative fungicide applications to control primary infections in high-pressure locations (e.g. near tree lines). In particular, fungicides in FRAC 3 (e.g. Indar, Tilt, and Cevya) are among the most effective site-specific products. That said, some biological fungicides also have been shown to be effective if applications are timed appropriately.

Don't Guess, Test!

The diagnostic program supported by the Michigan Blueberry Commission (MBC) first piloted last year, is continuing in 2023. This program funded by the MBC will cover the diagnostic fees for up to two samples per Michigan blueberry grower. The samples will be evaluated and tested as appropriate by specialists in the MSU Plant & Pest Diagnostics (PPD) lab.  If there is anything concerning or puzzling in your blueberry field, be sure to take advantage of this opportunity.

Mummy Berry Fact Sheet
Mummy Berry Diagnostic Guide
Diagnostic Testing Form 
Don't guess, Test! Mummy Berry

Horticulture Update: Spring Frost Update

We are nearing the frost-free date of May 16th. Although chances for a damaging spring frost event are quickly diminishing, blueberry cultivars that are nearer to bloom (early-season) than bud break (mid- and late-season) stand a higher chance of freeze damage in the event that a spring frost event does occur in the next two weeks. Most blueberry cultivars are cold-hardy to a temperature of about 20 °F (-7 °C) at the bud burst stage, 25 °F (-4 °C) at the pink bud stage, and 27-28 °F (-2 to -3 °C) at the open flower/petal fall stages.   

Horticulture Update - Replanting Blueberries

With replanting in mind, May is a good month to remove blueberry plants. There are many decisions to make surrounding this process, including: "which cultivars to remove," "how to remove plants," "how many months/years to fallow the soil," and "how to re-establish plants with current horticultural practices." A general guide for replanting blueberries was recently published by MSU.   

Sprinklers for frost protection
Replanting Best Practices

Extension Update

The southwest fruit team hosts weekly IPM meetings feel free to join us in-person or virtually from 5:30-7 at the southwest Michigan Research and Extension Center. 1 RUP credit is offered each week. Sign up here!

Give it a listen!

The United States Highbush Blueberry Council puts out a podcast every week - The Business of Blueberries. They cover a variety of topics and always have a crop update for the different growing regions. Check it out here or wherever you get your podcasts.

Upcoming Events




Pollinator Workshop - South

May 17, 10 am -Noon

Grand Junction

Pollinator Workshop - North

June 1,10 am - Noon

West Olive

Blueberry Bites is compiled by Cheyenne Sloan, Blueberry and Small Fruit Educator

Contributors: Rufus Isaacs, Josh VanderWeide, Tim Miles, Cheyenne Sloan

Questions? Comments?

MSUE Small Fruit Educators

Blueberry and Small Fruit Educator - Cheyenne Sloan

Small Fruit Educator - Carlos Garcia Salazar

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