Figure 2. Symptoms of laurel wilt fungal (Raffaelea lauricola) colonization of redbay trees. a) Removing the bark reveals dark staining of the sapwood. b) The dark color of the outer ring of sapwood below the bark indicates the tree has been infested by the redbay ambrosia beetle and the wood has been colonized by the laurel wilt pathogen. The fungal hyphae, which have colonized sapwood, block movement of water and nutrients in the tree.
Credit: Albert Mayfield, Florida Department of Agriculture and Consumer Services