Effect of plant roots on the germination of microsclerotia ofVerticillum dahliae

Root observation boxes were used to study the effects of hosts and non-hosts on the germination of microsclerotia ofV. dahliae. The effects of roots on microsclerotia were examined within a radius of 1 mm around the root tip. Host plants such as potato and field bean induced a higher percentage of germination of the microsclerotia than a non-host such as barley. A susceptible potato cultivar stimulated germination more than a resistant cultivar. The germination percentage and the number of hyphae per microsclerotium decreased with distance from the root surface regardless of the plant species or cultivar.