The Russian olive is so susceptible to the canker and dieback caused by Phomopsis elaeagni that it is no longer considered suitable as an ornamental shrub or small tree. Symptoms are a typical dieback of branches in the uppermost portion of the canopy. Young green shoots may wilt and die and leaves remain withered and attached. The sapwood below the dead, orange-brown bark turns black, and the discoloration extends beyond the canker. The fungus will infect even healthy, vigorously growing plants.
Infection can occur throughout the growing season whenever rain and wounds are present.
Spores ooze from fruiting bodies on the dead, orange-brown bark whenever rains wet the branches. Otherwise, prune out dead branches and revitalize the root system as described under General decline and dieback. No fungicides are effective for control of Phomopsis on Russian olive. This information is for educational purposes only. References to commercial products or trade names does not imply endorsement by MSU Extension or bias against those not mentioned.