Control of Mal secco disease in lemon by drip irrigation of fungicide

Abstract The ‘mal secco’ disease of citrus is caused by the mitosporic ascomycete fungus Plenodomus tracheiphilus (formerly Phoma tracheiphilus (Petri)). Mal secco of citrus is a highly destructive vascular disease of lemon and other citrus, presently confined to the Mediterranean basin, which has a relevant economic impact on the citrus industry. The fungal pathogen infects the host tree by penetrating through wounds in the roots or the canopy. Canopy infection spreads quickly into the main branches and trunk and tree mortality usually occurs. The most typical symptoms are venial chlorosis, leaf wilt, red coloration of the xylem and die back of twigs and branches. Current acceptable control of the disease is mainly by sanitation of infected wood, and cooper application during the winter, to prevent germinating spores from infecting the plant. No effective chemical control was reported for the control of the disease. Here we report the development of a drip irrigation protocol for the protection of trees and the control of the disease by applying Futriafol 125 gr/liter, five times during the year. The progress of the disease symptoms in the treated trees is inhibited dramatically allowing the sanitation process to become easier, significantly shorter to perform, and cheaper than in untreated trees. The longer the orchard is treated, the less symptoms of the disease are diagnosed in the trees. We have treated orchards for more than six years and established a commercial protocol for the growers, helping them to control the disease.