Saprophytic Behaviour Of Some Cereal Root‐Rot Fungi

The ability of four cereal root‐rot fungi, Helminthosporium sativum, Curvularia ramosa, Ophiobolus graminis and Fusarium culmorum , to colonize wheat straw as saprophytes has been investigated. Test pieces of straw were buried in a graded dilution series of maizemeal‐sand culture of the test fungus with unsterilized soil. For assessing percentage straws colonized, three methods were compared: (1) isolation on agar plates, (2) Garrett's (1938 b ) wheat‐seedling test and (3) incubation on moist sand, to promote sporulation (the ‘sand‐plate’ test). Curvularia ramosa and Fusarium culmorum were found to behave as vigorous competitive saprophytes of the soil‐inhabiting type, whereas Helminthosporium sativum and Ophiobolus graminis proved to be weak saprophytic colonizers of the specialized root‐inhabiting type.