What disease is affecting aspens in Bend?

Asked January 20, 2020, 2:19 PM EST

We have aspens in our yard on Bend's west-side. The past couple of years the leaves have been turning brown and the trees are sickly-looking. We see the same affliction on other aspens in the area. Consultation with local tree services resulted in a variety of suggested causes, but no acknowledgment that they had observed this affliction. Have you observed this and do you know the cause/have a recommended solution? Our aspens have been watered well. Thank you.

Deschutes County Oregon

1 Response

Hi, The most common reason we see leaves browning on aspen in this region is from the aspen leaf blotch miner : https://extension.oregonstate.edu/pests-diseases/insects/common-insects-found-central-oregon This pest generally does not cause plant dieback just makes the leaves look bad which can be alarming, but will not kill the tree. Some years are more noticeable than other. The larval stage will mine between the top and bottom leaf tissue so most do not see the insect. The second pathogen that may cause browning of the leaves here is Marssonina leaf blight. https://extension.colostate.edu/topic-areas/yard-garden/aspen-and-poplar-leaf-spots-2-920/ The best way to know how to manage what your seeing is to first identify the issue. I would recommend you send me a photo or bring a sample this coming year if you are seeing the same problem. Feel free to call me at the number below to further discuss.