Orange rust on Asian pears

Asked June 23, 2019, 5:04 PM EDT

What causes the orange rust on Asian pears and how can I get rid of it. I didn't have a problem last year and the pairs are really good.

Lane County Oregon fruit trees rust asian pear

1 Response

Your pear tree is infected by Pacific Coast Pear Rust. (If it's any consolation, many other pear trees in our region also have rust this year.) Significant outbreaks occur every several years. Both Asian and European cultivars are susceptible. Most rust diseases are interesting in that they require two hosts to complete the life cycle. With Pacific Coast Pear Rust the alternate (2nd) host is incense cedar. At the time pears were in flower, bright orange telia (jelly-like blobs; the fungus) were on the infected . Airborne spores from the jelly masses infect susceptible pears, both flowers and leaves. In order for a spray to be effective, it must be applied when the swollen, orange telia are present on the cedars. In western Oregon, that’s usually during bloom. (In other words, it’s too late to spray this year.)

Your strategy for the remainder of this year will include (1) good sanitation (collect and discard infected leaves and fruit); (2) remove and discard any infected woody parts;

Here is a publication you should check out:

https://pnwhandbooks.org/plantdisease/host-disease/pear-pyrus-spp-pacific-coast-pear-rust

Hope this helps!