Cumin wilt incited by F.oxysporum f.sp cumini Prasad & Patel is the most destructive disease of this crop in Khorasan province and causes considerable yield loss. Two species of antagonistic fungi were isolated from cumin fields soil, using Davet medium and identified as Trichodrma harzianum (4 isolates T1 - T 4) and Gliocladium vb.ens (2 isolates G1 and G2) according to Rifai (1969) and Domsch et ale (1980). The effect of 6 antagonistic fungal isolates and 4 fungicides were studied on Fusarium in viro and in vivo. Microscopic studies showed that the hyphae of antagonistic fungi by contacting and coiling, caused deformation and lysis of Fusarium hyphae. In dual culture test, all antagonistic isolates had a much faster growth rate comparing to Fusa rium and reduced the pathogen colony diameters considerably. The volatile metabolites of all Trichoderma and Gliocladium isolates affected Fusarium. The 96 h. old culture of T4 isolate had the best effect and inhibited mycelial growth of the pathogen by 16.08%. The culture filtrates of G1 isolate at 30% concentration had the most effect and inhibited mycelial growth of F usa r i u m by 36.62%. Benomyl, Rovral T. S. (Iprodione-carbendazim), carboxin-thiram and captan at 10 mgllit. reduced Fusarium mycelial growth by 100, 85, 39, 5, 42, 45, 88 percent respectively and also the ECso of these fungicides were 1.63, 1.86, 6.85, 14.18 mgllit. respectively. Under greenhouse conditions, seed dressing with T.harzianum T2
. isolate, lowered disease incidence by 65.4,% and showed to be more effective
than seed treatment with fungicides. In greenhouse adding inoculum of antagonistic fungi to pots decreased disease incidence considerably and T 2 isolate with 62.5% disease reduction was most effective.
)