Abstract

In vitro, sensitivity of Macrophomina phaseolina (Tassi) Goid determined through inhibition zone technique to various antagonistic fungi viz., Aspergillus niger, Aspergillus flavus,Trichoderma viride, Trichoderma harzianum and Penicillium capsulatum amended into PDA medium. All the antagonists reduced the colony growth of M. Phaseolina significantly compared to the control A. flavus was proved to be the most effective (66.00%) in reducing the colony growth of M. Phaseolina followed by A. niger (55.55%), T. viride (51.11%), T. harzianum (26.67%) and P. capsulatum (11.11%) respectively over control. A. flavus due to it antifungal metabolites activities was the most effective while P. capsulatum was the least effective. Seeds of four varieties treated with the culture of A. flavus, A. niger, T. viride andP. capsulatum and there combinations were sown in pots having infested soil (M. phaseolina). Results showed reduction in disease incidence of charcoal rot on sunflower cultivar G-66 with antagonist, A. flavus (100%) followed by A. niger (64.86%) P. capsulatum(63.79%) and T. viride (31.89%) over control. Decrease in disease incidence over control was 100% where seed was treated with combination of A. niger and A. flavus while A. nigerand T. viride combination was least effective on G-66 (30.80%). All antagonists reduced the disease incidence on G-66 (Highly resistant), HRBS-1, (Resistant), G-72 (Moderately susceptible) and G-51 (susceptible) but were most effective on highly resistant variety (G-66) while least effective on susceptible variety (G-51).

Key words: Sunflowers, Macrophomina phaseolina, antagonistic fungi