Interactions between Sclerotium cepivorum and cultivars of onion, leek, garlic and Allium fistulosum

Laboratory and field experiments showed that germination of sclerotia of Sclerotium cepivorum was slower in the presence of cultivars of leek than in the presence of those of onion, garlic and Allium fistulosum . Spread of infection amongst closely spaced plants was also less in leeks than in the other three species. No evidence was found for any differences in the resistance of root tissues of the four Allium species. It is considered that differential stimulation of sclerotium germination is likely to have been the principal reason for the low incidence of white rot infection in leeks which was reported previously.