Evaluation of Trichoderma Isolates for Biological Control of Charcoal Stem Rot in Melon Caused by Macrophomina phaseolina.

Trichoderma harzianum (t39), t.virens (dar74290), t.viride (mo), t. harzianum (m) and trichderminb a commercial formulation of t. harzianum(bi) were evaluated as potential biological agents for the control of charcoal stem rot in melon caused by macrophomina phaseolina. cell-free metabolites of t. harzianum(m), t. harzianum (t39) and t. virens (dar 74290) inhibited growth of m. phaseolina completely in vitro and appeared to be fungicidal. t. viride (mo) inhibited fungal growth from 34.9% to 71%. t. harzianum (t39), t. harzianum (m), t. virens (dar 74290), t. viride(mo) and t. harzianum (bi) were tested for their ability to protect melon plants from disease caused by m. phaseolina in a glasshouse experiment. the percentage of stand plants with the antagonist alone or in combination with the pathogen was significantly (p<0.05) greater than in plants inoculated with the pathogen alone. the percentages for the stand plants in treatments were as follows: t. harzianum (t39), t. harzianum (m), t. virens (dar 74290), m. phaseolina, m. phaseolina + t. virens (dar 74290), m. phaseolina + t. harzianum (t39) and m. phaseolina + t. harzianum (m),at 95, 100, 97.5, 15, 64.25, 75.25 and 47.55 percent respectively. the percentage for the stand plant in the commercial trichodermin b + m. phaseolina treatment (96.7%) was greater than for m. phaseolina alone (46.7%) and demonstrated the best result in the control of charcoal stem rot in melon.