Figure 3.

(A) Old canker on a secondary branch of lemon tree with longitudinal bark splitting at the base of the branch and the gum exudate in the advancing upward front, indicating the canker is still active; (B) the same as (A) after peeling the bark to show the dark brown discoloration of the wood beneath the bark; (C) typical chocolate brown discoloration of the wood underneath the bark; (D) a detail showing the necrotic bark of the canker exuding gum and the typical chocolate brown wood discoloration beneath the bark.