Reaction of muskmelon and cantaloupe landraces to root rot and vine decline disease caused by Monosporascus cannonballus

Root rot and vine decline caused by Monosporascus cannonballus is the most destructive diseases of cucurbitaceous plants in arid and semi-arid regions across the world. Control strategies of this disease in Iran have remained elusive so far, despite its devastating importance. In this study, pathogenicity potential of eight isolates of M. cannonballus was assessed on a susceptible landrace of melon, locally named Zard-e-Garmsar. The most virulent isolate was then used to inoculate 31 landraces and cultivars of cantaloupe and muskmelon in two independent experiments. The reaction of the landraces was assessed through measuring disease incidence, disease severity and the weight of root and shoot. The minimum disease incidence was observed as 62.5, 66.67, 70.84, 79.17 and 79.17 in landraces Ghasri Mashhadi, Biarjmand, Minoo095, Shah Abadi and Zeydary respectively. The minimum disease severity was measured as 27.5%, 29.5%, 31.5%, 32% and 27% in these landraces accordingly. The maximum weight of roots and shoots were measured for these landraces. This study showed that disease incidence and disease severity was occurred in lower amounts in landraces of Ghasri Mashhadi, Zeydary, Biarjmand, Minoo 095 and Shah Abadi in which produced higher amounts of root and shoot tissues among landraces tested. These landraces therefore, can be recommended for field trials.