INTERACTIONS BETWEEN TRICHODERMA-KONINGII, FUSARIUM-SOLANI AND GLOMUS-MOSSEAE - EFFECTS ON PLANT-GROWTH, ARBUSCULAR MYCORRHIZAS AND THE SAPROPHYTE INOCULANTS

The effect of inoculation with the saprophytic fungi Trichoderma konin gii and Fusarium solani on maize (Zea mays) and lettuce (Lactuca sativ a) with or without arbuscular mycorrhizal (AM) colonization by Glomus mosseae was studied in a greenhouse trial. Plant dry wt of non-AM inoc ulated maize and lettuce were unaffected by the presence of T. koningi i and F. solani. In contrast, T. koningii decreased plant dry wt and A M colonization when inoculated into the rhizosphere before or at the s ame time as G. mosseae. In addition, the T. koningii population was co nsiderably reduced when G. mosseae was inoculated 2 weeks before the s aprophytic fungus. At this time T. koningii did not affect the proport ion of the root length colonized by G. mosseae, but did adversely affe ct its metabolic activity assessed as succinate dehydrogenase activity . Although F. solani did not affect AM colonization of maize roots, it s effect on AM colonization of lettuce roots was similar to that of T. koningii. The population of F. solani decreased significantly in the rhizosphere of both plants. The possible mechanisms of interaction bet ween the saprophytic fungi and G. mosseae are discussed.