Myrtle defoliation caused by a plant pathogen, Calonectria californiensis, has been observed in Coos and Curry Counties. Defoliation starts at the bottom of the tree and proceeds upward. Defoliation can be significant, affecting 80% of the tree.

Leaf symptoms include tan colored spots and blotches surrounded by dark brown margins. Once infested, the leaves can drop off the tree quickly.

Many Oregon-myrtle trees affected by the pathogen appear to have new foliage growth which is very promising. We are in the process of developing a data sheet where interested landowners can help us monitor the health and environmental settings of their myrtles. At this point, unless a tree poses a particular hazard, we suggest that landowners take a wait-and-see approach to tree health recovery. Once we gather sufficient information, we plan to develop a fact sheet. Calonectria californiensis may also affect other native trees and shrubs such as salal, mock orange, Oregon grape, native rhododendrons and tanoak.  Calonectria IS NOT the same pathogen that causes Sudden Oak Death in Curry County.

Oregon-myrtle identification. Oregon-myrtle (Umbellularia californica) goes by several common names: Oregon-myrtle, bay laurel, California-laurel, California bay, pepperwood. They are all the same tree! Oregon-myrtle is a broadleaf evergreen tree with highly aromatic thick and leathery leaves. The small, greenish fruit are less than 1 inch long.

Are you interested in participating in the Oregon-myrtle monitoring project? Contact Norma Kline, OSU Extension Forester for Coos and Curry Counties. Norma.Kline@Oregonstate.edu