Characterization of Local Trichoderma spp. as Potential Bio-Control Agents, Screening of in vitro Antagonistic Activities and Fungicide Tolerance

Abstract

Enlightening effects of biocontrol agents as Trichoderma spp. to provide disease control by combating pathogens is an important alternative in agricultural crop production. To that end, 9 species of Hypocrea/ Trichoderma having green ascospores isolated from the soil that tea plants cultivated in are identified by ITS sequences and were found to be close relative of Trichoderma sect. Pachybasium (77%). Ethyl acetate extracts of fungal isolates exhibited the antimicrobial activity against to Vibrio sp, Serratia marcescens, Mycobacterium smegmatis and Bacillus cereus but no antifungal activity was detected. The highest level of inhibitory activity was observed against to M. smegmatis by Trichoderma harzianum ID4A, ID4B and ID6B. In dual culture test, all Trichoderma strains were found to be showing the highest inhibitory activity against to the plant pathogens Botrytis cinerea, Sclerotonia sclerotiorum and Rhizoctonia solani (AG3), but relatively low activity against to the entomopathogen fungi. Volatile metabolites of Trichoderma spp. caused maximum reduction in mycelial growth and sclerotial production. Tested strains showed the highest tolerance to the fungicide Dikozin, whereas the lowest tolerance was against to the Captan regardless of the dosage.