japanese ornamental plum tree disease concern

Asked September 30, 2016, 8:55 AM EDT

Our Japanese Ornamental Plum Tree has suddenly started excreting a translucent, amberish gum substance. Online research indicates it may be a form of fungal canker disease. When researching for a remedy, all sources said to contact the local county extension office. The tree was planted 11 years ago and has had no visible issues, other than being a prime target for Japanese Beetles, although this year was very light in terms of the Beetle. The location of the tree allows it plenty of access to moisture in the ground after rain events. The area has a good water retention/drainage balance. What do you recommend on how to counter this fungal condition?

New Castle County Delaware

1 Response


Cherry trees and other trees in the Prunus Family, ooze amber liquid or gum when wounded or stressed. We sometimes call this gummosis. Look for a wound or canker lower on the branches or on the trunk. If the wound is not on the main trunk, the tree may be pruned by a professional. A professional may be a tree care specialist or arborist. If there is gum on the tree, do not remove it or scrape. It may be promoted by the wet weather we have had and will diminish when weather becomes more dry. It is not a fungal infection, but may have some bacteria in the gum. The Japanese beetles only feed on foliage and will not have long lasting effects.
Insects such as borers are attracted to stressed and wounded trees, so watch for insect involvement.
Re-evaluate the tree in the spring.

Thank you for contacting Cooperative Extension.