Nematicidal efficacy of native Trichoderma isolates on Meloidogyne incognita and their influence on tomato growth parameters

Abstract

Root-knot nematodes (RKN), particularly Meloidogyne incognita, pose a major threat to global agriculture, causing significant crop losses. While fungal antagonists like Trichoderma spp. offer eco-friendly alternatives to chemical nematicides, limited research exists on the comparative efficacy of native Trichoderma spp. in controlling M. incognita and enhancing plant growth under both controlled and greenhouse conditions. This study aims to bridge this gap by identifying the most effective Trichoderma spp. with strong nematicidal potential. The primary objectives of this study were to evaluate the nematicidal activity of 167 Trichoderma isolates against M. incognita second-stage juveniles (J2) under in vitro conditions, assess the most potent species in greenhouse conditions for their ability to suppress root galling and nematode population, and determine the impact of these species on tomato plant growth parameters. A total of 167 Trichoderma isolates were screened in vitro for their ability to induce mortality in M. incognita second-stage juveniles (J2) at 24, 48, and 72 h. The most effective species were further tested in greenhouse conditions using Trichoderma conidial suspensions (10⁶ spores/mL) to assess their impact on root galling, nematode population density, and tomato growth. Among them, 22 isolates exhibited strong nematicidal activity (70 %) within 72 h, with T. asperellum SolT6b achieving the highest J2 mortality (91 %), followed by T. afroharzianum ST10 (88.63 %). In greenhouse conditions, SolT6b and ST10 significantly reduced root galling (by 90.4 % and 89.3 %, respectively) and J2 soil populations (by 67.7 % and 66.6 %, respectively) compared to untreated controls. Additionally, Trichoderma treatment enhanced root biomass and overall plant vigor. These findings highlight the potential of native Trichoderma spp. as sustainable biocontrol agents against M. incognita, offering an effective alternative to chemical nematicides and paving the way for Trichoderma-based biocontrol formulations.