The relationship between the spore density of Cochliobolus sativus in soil and its saprophytic activity and parasitism

Abstract

Both saprophytic colonization of wheat straw and seedling infection by Cochlioholus sativus (Ito and Kur.) Drechsl. ex Dastur, which causes common root rot of wheat, were correlated with spore density. The results indicate that straw colonization is possible at 10�C even when the spore density is too low to cause seedling infection. Saprophytic activity may thus raise the spore density over the threshold necessary for parasitism.