Characteristic hazelnut decline symptoms observed on hazelnut plants (cv. Tonda Gentile Romana). Decline began with sudden wilting of a stem (A) while the rest was still intact. Successively, decline affected the whole branch which manifested the dieback while the remaining branch manifested suffering state with pale green foliage (B). When the bark of branch bearing pale green foliage was excised, discoloration of cambium could be observed (C). During the end of vegetative phase complete plant death occurred although leaves were still attached (D). The following year, also the plants present in the proximity of the plant that showed initial decline symptoms appeared completely affected (E).