Evaluation of antagonistic strains of Trichoderma spp. against Phytophthora sp. on Tectona grandis L.f.

Abstract

This study evaluated the antagonism of Trichoderma spp. against Phytophthora spp. the pathogen responsible for dieback on Tectona grandis (teak), with the aim of proposing a biological alternative for its control. Trichoderma and Phytophthora were isolated from soil samples of affected plantations, using PDA and V8 Agar media. In vitro antagonism tests were carried out using dual cultures to measure the Percentage of Radial Growth Inhibition (PGRI) of Phytophthora spp. The selected Trichoderma strains were morphologically and molecularly characterised to ensure their identification. The results showed that strains such as T. virens and T. harzianum significantly inhibited the growth of Phytophthora spp. demonstrating a high potential for biological control of the disease. The antagonism observed in the in vitro tests indicated that these Trichoderma strains can reduce the spread of the pathogen under controlled conditions. These findings highlight Trichoderma as a viable and sustainable alternative to the use of chemical fungicides, offering a more environmentally friendly management strategy for the protection of teak plantations. The molecular characterisation of the strains and their ability to inhibit the pathogen reinforce the effectiveness of Trichoderma as a biocontrol agent. This approach is relevant to encourage more sustainable agricultural practices, promoting vigour and productivity of teak forest plantations.