Cause An unknown leaf spot is common in landscapes and gardens in western Oregon. The main symptom is a brown necrosis of the underside of the leaf that looks like a network of lines on the margins of the leaf spot. Spots may be numerous and generally occur between the leaf veins. Tops of leaves may show no symptoms at all or more subtle necrosis between the veins. Symptoms were not apparent when surveying in early June 2022 but by July spots were quite numerous on plants throughout OSU campus. No biotic causes have been found and although ozone injury is suspected it does not account for all observations.
Pacific Northwest Plant Disease Management Handbook
Printed page URL: https://pnwhandbooks.org/node/23901
Fothergilla-Leaf Spot
Latest revision:
March 2024
Netted leaf spot on underside of leaf with subtle injury on top.
Jay W. Pscheidt, 2012.
Although these spots look somewhat like ringspots it was negative for viral particles.
OSU Plant Clinic image, 2018.
The leaf damage is unknown but ozone is suspected due to the distribution of symptoms on plants and leaves.
OSU Plant Clinic image, 2012.