Mal secco may be a disease caused by the conidia-producing fungal plant pathogen Phoma tracheiphila. It mainly causes the disease to citrus trees in the Mediterranean. In particular, it causes damage to lemon trees in the Mediterranean basin. The plant pathogen, Phoma Tracheophyta, is rain- and wind-disseminated. Symptoms normally appear early within the spring as chlorosis of the shoot and leaf vein. There is also epinasty, or bent out and downwards, of the young leaves within the spring. This is followed by wilt and dieback of leaves, twigs, and branches. In most cases dieback is sectorial. Symptoms start out by resembling frost damage of the leaves and gradually progress to leaf and stem dieback. A salmon, pink, or red color develops within the wood thanks to the xylem producing a gum to stop further damage.
