Canes obtained from one-year-old stems of the grapevine cultivars Cabernet Franc,
Malbec, Merlot, Sauvignon Blanc and Syrah (all non-grafted) were used as models to test
their susceptibility to Diplodia seriata and Diplodia mutila. The results showed that the mean
length of lesions caused by D. mutila was 3.2 times larger than that produced by D. seriata. In
addition, the Cabernet Franc and Syrah cultivars were the most susceptible to D. mutila, while
Merlot and Malbec were the least susceptible. No significant differences were observed between
cultivars inoculated with D. seriata. The results are discussed in terms of the susceptibility of
the different grapevine cultivars to both pathogens.