Abstract

 Response of three biocontrol agents including Trichoderma harzianum T969,Trichoderma hamatum T614 and Trichoderma virens T525 in the presence of 0, 50, 91.2, 166, 302, 550 and 1000 mg/l concentrations of MgSO₄.7H₂O, ZnSO₄.7H₂O, CuSO₄, FeSO₄.7H₂O, MnSO₄.H₂O, CoCl₂.6H₂O, CaCl₂.2H₂O and (NH₄)₂SO₄ via poisoned medium method, were studied. Radial growth of theTrichoderma isolates were recorded 48 and 72 h after inoculating. For each experimental set, experimental design used was completely randomized design (CRD) through factorial experiment with 3 factors. Also, inhibition percentage of the fungus mycelia growth due to metal containing compound at the inhibitory effect exhibited compound was calculated. The experiments indicated that Trichodermaspecies mycelia response to the compound differed noticeably in their sensitivities to the metal containing compounds and fertilizers exposure. ZnSO₄.7H₂O, CuSO₄, FeSO₄.7H₂O, MnSO₄.H₂O and CoCl₂.6H₂O compounds were effective as radial growth inhibitors, though (NH₄)₂SO₄, MgSO₄.7H₂O and CaCl₂.2H₂O were found to be non-toxic to the Trichoderma species. Meanwhile, CuSO₄ indicated the strongest inhibition towards the in vitro mycelia expansion of the fungi.

Key words: Metal containing compound, fertilizer, biocontrol agent, mycelia growth, EC₅₀, inhibition.