Gouveia, Maria EugéniaCoelho, ValentimAraújo, JorgeMoura, Luísa2020-03-192020-03-192019Gouveia, Maria Eugénia; Coelho, Valentim; Araújo, Jorge; Moura, Luísa (2019). Biological hypovirulence by hypovirus - CHV1: a success story of chestnut blight biocontrol in Portugal. In XIX International Plant Protection Congress 2019 (IPPC2019). Hyderabadhttp://hdl.handle.net/10198/21056The European chestnut (Castanea sativa Mill.) is a very important tree on mountain regions in Portugal. Chestnut Blight is associated with the fungus Cryphonectria parasitica (Murrill) Barr. This pathogen is an A2 quarantine organism that was introduced in 1989 and is establishes in all regions of C. sativa in Portugal. In some places, the incidence of the disease may reach the dramatic values of 100%. Hypovirulence is a biological process in which the aggressiveness of C. parasitica is reduced by fungal virus infection (Hypovirus), which has been shown to be effective to control the disease by promoting canker healing and chestnut recovery. Based on the rationales of hypovirulence, a program for chestnut blight biocontrol was applied in Portugal. The program lays in a first stage, on the study of the C. parasitica population related with vegetative incompatibility system (vic type), and in a second stage, on the application of the compatible hypovirulent strain to each active canker. The program for the chestnut blight biocontrol includes several entities such as the Polytechnic Institute of Bragança, the Chestnut Treatment Organizations and the chestnut producers. Since 2015, the program had the participation of 907 chestnut producers, which treated 32053 chestnut trees in 1813 chestnut orchards. The results obtained in this program, that needs to be continued for a more extended time, point forward for a success story and chestnut blight disease has been controlled by this selective and efficient hypovirulence biological method.engChestnut BlightBiocontrolconference object