Mechanisms Involved in Biological Control of Fusarium Wilt of Cucumber with Strains of NonpathogenicFusarium oxysporum

Two nonpathogenic strains of Fusarium oxysporum (C5 and C14) introduced into soil at 1.08× 10 4 and 5× 10 4 colony-forming units (cfu) per gram of soil significantly decreased the slope values of inoculum density-disease incidence curves generated for Fusarium wilt of cucumber induced by F. oxysporum f. sp. cucumerinum. Strain C14 reduced disease significantly more than C5. A three-phase mechanism was associated with biological control of Fusarium wilt by these agents. There was a significant reduction in germination of chlamydospores of F. o. cucumerinum in the rhizospheres of cucumbers infested with C5 or C14 (...)