Initially, infected trees have scattered dead branches. Brown streaks in sapwood. Leaves wilt, turn yellow and brown. Terminal parts of tree affected first and later the entire tree. Brown discoloration occurs in sapwood just under bark in wilting branches.
Positive identification requires laboratory culturing.
Send specimens to the Extension Plant Diagnostic Clinic. Flagging of leaves on affected branch. There is no control for Dutch elm disease once the infection reaches the trunk and roots. Dutch elm disease can be transmitted from a diseased elm to an adjacent healthy tree through root grafts. Therapy for infected trees is questionable.