Incidence and spatial pattern of viruses in commercial dragon fruit orchards in southern Minas Gerais, Brazil

Dragon fruit (Selenicereus spp. syn. Hylocereus spp.) cultivation has grown significantly in recent years both in Brazil and throughout the world. This growth has demanded basic information on diseases caused by pathogens that can affect the crop. Among them, diseases of viral etiology stand out for the lack of curative control methods and for being underreported because the symptoms induced by viruses can be confounded with nutritional disorders. Previously, four viral species of the genus Potexvirus were detected in samples from different regions of Brazil. The objective of this study was to determine the incidence and spatial distribution of potexviruses in 12 commercial dragon fruit orchards in the south of Minas Gerais. The number of plants evaluated for incidence was calculated based on the size of each orchard, and the spatial distribution was investigated throughout the area. High incidences of potexviruses were detected, ranging from 80 to 100%. The spatial distribution of diseased plants showed an aggregated pattern in planting rows and a regular pattern in plots, indicating dissemination through cultural operations and infected seedlings as a source of inoculum. This was the first study on the epidemiology of viruses in dragon fruit orchards, and the data obtained indicate that producers are unaware of control measures required to manage the disease. In addition, the results showed the need to control seedling commercialization, aiming at the propagation of healthy material, along with the use of appropriate management practices to decrease the spread of viruses within orchards.