SURVIVAL OF DIDYMELLA-RABIEI IN CHICKPEA STRAW DEBRIS IN SPAIN

Didymella rabiei grew saprophytically on pieces of infested chickpea s tems and pods, and formed pycnidia and pseudothecia. The extent of sap rophytic growth and production of viable spores were determined by the incubation conditions. On debris left on the soil surface under natur al conditions, the fungus rapidly colonized the tissues, formed abunda nt pseudothecia and pycnidia, and remained viable throughout the 2 yea rs of the study. When plant debris was buried, D. rabiei was restricte d to the original lesions, in which it formed new pycnidia and was via ble for 2 to 5 months. Under controlled conditions in the laboratory, D. rabiei extensively colonized plant debris spread over the soil surf ace. On the other hand, the fungus did not grow on buried debris, or s howed only very limited development when the artificially infested deb ris was buried between two layers of sterilized soil. Incubation tempe rature was the principal factor associated with the production of coni dia and especially ascospores.