In-vitro effect of newer fungicides on mycelial growth in biocontrol fungus Trichoderma harzianum (Th 14)

Trichoderma harziaum (Th 14) was tested in vitro for its compatibility with different concentrations of commonly used newer fungicides. Six systemic viz., hexaconazole, tubunaconazole, difenaconazole, propinconazole, carbendazim and two contact fungicides mancozeb and captan were used, each at concentrations of 25, 50 and 100 ppm. A progressive increase in percent inhibition of radial growth in the fungus was observed as the concentrations of the fungicides increased. Among the systemic fungicides 100% growth inhibition was recorded at all the concentrations tested except metalaxyl. Toxicity of the contact fungicides was lower than the systemic fungicides, among which mancozeb was compatible, no inhibition was observed at lower concentration (25 ppm). The inhibition ranged from 8.75 to 23.75% for metalaxyl, from 4.58 to18.33% for mancozeb and from 14.75 to 32.91% for captan and increased with increase concentration. These results will help delineate the possibility of combining T. harzianum biocontrol agents and fungicides for use in an integrated disease management approach.