Hello Erin,

Based on the images that you sent...

It sounds like your Downy Serviceberry might be dealing with a fungal infection—Quince Rust is a likely culprit. This disease, caused by Gymnosporangium clavipes, can affect the fruit and stems, leading to swelling, distortion, and the appearance of tubular, white fungal structures that give the fruit a fuzzy or spiky look. Over time, the infected berries may rot or become discolored. More information at this link:

What's wrong with my plant? : Garden : University of Minnesota Extension

What to Look For

Brown fuzz or spiky growths on berries

Swollen or distorted fruit and stems

Bright orange or white fungal structures

Premature fruit drop or decay

 Treatment & Management

Prune and remove infected fruit and branches to reduce the spread of spores.

Avoid overhead watering to limit moisture on foliage and fruit.

Improve air circulation by thinning nearby vegetation.

Fungicide applications may be beneficial, especially early in the season; consult your local extension office for timing and product recommendations.

Remove nearby junipers, which can serve as alternate hosts for rust fungi.

BEFORE YOU DO ANY TREATMENT OR MANAGEMENT – CONSULT WITH MSU PLANT AND PEST DIAGNOSTICS!

I highly recommend sending your images by email to the MSU Plant & Pest Diagnostics Lab to receive a confirmed and precise diagnosis.

Their email is <personal data hidden> - Please include your first and last name.

The experts there can also provide you with the best treatment options.

The lab will notify you if they require a sample to be sent.

The lab may also ask for additional images. So be prepared.

Their website is at this link:

Plant & Pest Diagnostics (msu.edu)

Their Contact Information is at this link:

Contact Us - Plant & Pest Diagnostics (msu.edu)

This link will explain the details on submitting a sample to the MSU Plant & Pest Diagnostics Lab:

Submit Samples - Plant & Pest Diagnostics (msu.edu)