Short Communication<br><br><i>In vitro</i> evaluation of antagonistic potential activity and assay of culture filtrates of <i>Trichoderma harzianum</i> and <i>Trichoderma viride</i> against coffee wilt pathogen (<i>Gibberella xylarioides</i>)

Abstract

Isolates of Fusarium xylarioides, the causative agent of coffee wilt disease, were obtained from five coffees growing woredas in south western Ethiopia. The isolation was made from five Arabica coffee (Coffea arabica) trees with severe symptoms of coffee wilt disease. The ability of Trichoderma harzianum and Trichoderma viride to inhibit mycelial growth of F. xylarioides was evaluated in vitro. The result showed that use of Trichoderma spp caused a radial mycelial growth inhibition of pathogen by 66.2% (Fx.20) and 70.9% (Fx.22), respectively. The minimum percent of mycelial growth inhibition (53.7 %) was observed by T.viride on isolate Fx.16. Use of the cell free culture filtrates of T. harzianum and T. viride with concentrations of 3ml, 4ml and 5ml resulted in radial growth inhibition of the test pathogen. T. viride was found to be more efficient than T. harzianum. Similarly, in vitro evaluation of the culture filtrates showed an average of 63.6% mycelial growth inhibition by T. viride over the control on Fx.22. This study showed that T. harzianum and T. viride have potential to be used as biocontrol agents for inhibition of mycelial growth of F. xylarioides isolates. Trichoderma harzianum and T. viride must be evaluated and tested against coffee wilt disease in vivo and in field condition in different agro-ecological zones of coffee growing regions, in order to apply biocontrol agents in large areas to manage F. xylarioides in the country.

Keywords/phrases: Biocontrol agents, Coffee wilt disease, Fusarium xylarioides, Trichoderma harzianum, Trichoderma viride

Ethiop. J. Biol. Sci., 9(1): 67-77, 2010