Vascular discoloration in red oak branch is at the outer xylem.
Vascular discoloration in white oaks can occur within the xylem since white oaks may survive for some time after infection.
Crack in bark of red oak caused by mycelial mat of the oak wilt fungus.
The fungus causing oak wilt produces fungal mats under the bark. These produce pressure to break open the bark.
Sap feeding beetles that vector oak wilt.
Endoconidia of Bretziella (Ceratocystis) fagacearum. a= conidia, b= conidiophore
Endoconidia of Bretziella (Ceratocystis) fagacearum.