Plant Disease Management Handbook

Cause The fungus Golovinomyces sp. (possible G. oronii or G. vincae) was found on Vinca minor plants in western Oregon in 2019. Disease distribution was on leaves of landscape plants under eves of a home. Plants in the open or under cedar trees were not obviously infected.

By M. Nampijja, S. Crane, L. du Toit, and C. Ocamb

Bacterial leaf spot caused by Pseudomonas syringae pv. aptata in baby leaf Swiss chard crops. Photo credited to M. Nampijja, S. Crane, and L. du Toit, Washington State University.

By M. Nampijja, S. Crane, L. du Toit, and C. Ocamb

Cause Fusarium sp. is suspect. Fusarium oxysporum was found repeatedly during 2012 and 2013 in association with dying plants in Oregon seed fields. The fungus is soilborne and can survive in soil, often in plant debris, for at least several year as durable resting spores known as chlamydospores. The fungus can be spread by infested equipment or windborne or waterborne movement of infested soil.


Cause The fungus Cryptostroma corticale has been causing dieback primarily in sycamore maples (Acer pseudoplatanus), although several other species can also become infected. The disease has been found in eastern WA for many years and in 2020 in the Seattle area on sycamore maple, red maple (Acer rubrum), Japanese maple (A. palmatum), vine maple (A.