IN VITRO BIOCONTROL ACTIVITY OF TRICHODERMA HARZIANUM AGAINST SOME PATHOGENIC FUNGI ON TOBACCO

Abstract

Biological control is an environmentally friendly approach to the plant protection from diseases. It reduces use of a chemical pesticides and it is a contemporary and reliable model which can be introduced into integrated pest management system. The biocontrol activity of Trichoderma harzianum was evaluated against some fungal pathogens on tobacco. In vitro assays confirmed the main mechanisms involved in biocontol-mycoparasitism, antibiosis and competition for food and space. T. harzianum has a biocontrol activity against all tested fungi. It reduced the pathogen growth and completely overgrowth its colony. Their relative growth in the presence of the biocontrol agent was 13,75 to 62,66%. The percentage inhibition of radial growth ranged from 37,34 to 93,83%. Inhibition of the radial growth of R. solani is 61,10%. Inhihition of the leaf pathogen A. alternata is very high -86,64%. T. harzianum showed the highest antagonistic potential (96,95%) against P. parasitica var. nicotianae, and the smallest (68,67%) – in P. debarianum. This result suggests that T. harzianum can be used in biological control of economically most important fungal diseases on tobacco.