Quince has bumps with powdery orange backsides

Asked May 5, 2020, 6:15 PM EDT

This is a young quince, pictures taken today. What is this, is it a concern, and need I treat it? Thanks!!

Multnomah County Oregon

3 Responses

Thank you for the images. The quince has rust, a fungus disease.

Rust is a complex disease which requires 2 different hosts. In quince rust, juniper is the alternate host. If you have junipers nearby, consider removing either the juniper(s) or the quince.

Our official disease management publication has several chemical suggestions to prevent disease on quince in home gardens but does not state whether they are safe on fruit-bearing trees.
Both would be safe to use on ornamental quince. Read the labels to ensure their safe use.

The suggested products are these:
- Infuse Systemic Disease Control
- Spectracide Immunox Multi-Purpose Fungicide Spray

Thanks for the response. I've gone ahead and removed all visibly affected areas (leaves, mostly) and put in the green bin. Is that a suitable treatment given the time of year we're in?
I wonder: there's no cedar/juniper here. How far does it spread? Could it have come from 150ft away, for example?

The fungus spores move on the breeze. So, yes, 150 ft is possible.