Evaluation of Fusarium spp. and other fungi as biological control agents of broomrape (Orobanche ramosa)

During extensive surveys in fields, heavily infested by Orobanche ramosa in Southern Italy, a large number of fungi were isolated from infected parasitic plants. More than 50 isolates belonging to 15 different species were selected to assess their pathogenicity and virulence against broomrape. All isolates were tested using a plastic-bag system with tomato as the host plant. Some of the tested isolates that quickly caused necrosis and rotted the attached tubercles were further tested in pot trials in a greenhouse. Among them, an isolate of Fusarium oxysporum and another of Fusarium solani were promising. They strongly reduced the number and weight of emerging broomrape shoots (around 60%), or the number of tubercles attached to the host roots (by more than 70%). Isolates of Fusarium camptoceras and Fusarium chlamydosporum caused around 50% control of broomrape. The potential of using these fungi, some of which are proposed here for the first time as biocontrol agents of O. ramosa, is discussed.