Evaluation of Antifungal Activities of Trichoderma spp. Against Phytophthora spp.: In- Vitro Bioassay

Abstract

This study evaluated the antifungal potential of native Trichoderma spp. in inhibiting the growth of Phytophthora spp. Trichoderma spp. and Phytophthora spp. were isolated from rhizospheric soil and diseased chilli plants, respectively. The isolates of Trichoderma spp. and Phytophthora spp. were subjected to in-vitro laboratory bioassay under controlled environmental conditions following the dual culture method. The pathogenic Phytophthora spp. were isolated, purified using the hyphal tip method and identified based on key morphological features. The virulence of the Phytophthora spp. isolates was tested on detached leaves of the chilli plant. The Trichoderma spp. were isolated following serial dilution and characterized based on key morphology features. The in-vitro experiment to evaluate the antifungal properties of Trichoderma spp. against Phytophthora spp. was designed in randomized complete block design in three replicates. Three isolates of Trichoderma spp. namely, TCP1, TCP2 and TCP3 were tested for antagonistic activity against four different isolates of Phytophthora spp., namely, PP1, PP2, PP3 and PP4. Results revealed that TCP3 exhibited the highest inhibition, reaching 61.49% (PP1), 62.10% (PP2), 60.19% (PP3), and 36.11% (PP4). TCP1 also showed strong antagonism with inhibition percentages of 56.48% (PP1), 59.11% (PP2), 56.63% (PP3), and 34.07% (PP4). In contrast, TCP2 displayed lower inhibition values: 44.44% (PP1), 45.18% (PP2), 39.63% (PP3), and 32.41% (PP4). A two-way ANOVA revealed a statistically significant interaction between Trichoder-
ma and Phytophthora isolates (F (30, 82) = 7.261, p = 0.001), confirming variation in inhibitory efficacy.