Three different groups of symptoms of oak decline are described. Type A: Repeated defoliation by insects together with other factors and a final attack by Armillaria cause a rapid mortality of a large number of trees (Quercus petraea; Northern Bavaria). Type B: Partial yellowing of the crown and increasing number of dead branches. Virus as cause of this kind of damage could not absolutely be excluded (Quercus robur; Southern Bavaria). Type C: The chronic course of the disease resembles several characteristics known from other tree species, which are affected by forest decline (Waldsterben). It affects both oak species and is very widespread at several locations in Bavaria.
