Management of Root-Knot Disease in Chilli by Soil Application of Trichoderma Species

The present study evaluates the efficacy of four Trichoderma species, namely T. harzianum, T. viride, T. asperellum, and T. hamatum, against M. incognita in chilli (Capsicum annuum) cv. NS-1701-DS under polyhouse pot conditions. Inoculation of Meloidogyne incognita 1500 J₂/pot reduced the plant growth and yield of chilli by 25.4% and 28.0%, respectively. The application of Trichoderma species significantly reduced root-knot disease severity and improved plant growth, biomass accumulation, physiological attributes, and yield parameters compared with the nematode-inoculated control. Among the tested species, T. harzianum proved to be the most effective, reducing the galling by 60.0%, followed by T. viride (52.0%) and T. asperellum (38.0%). The T. harzianum treatment in the nematode infected plants significantly increased plant length, number of fruits per plant, fruit length, and fruit weight by 27%, 31.8%, 40.4%, and 33.7%, respectively, compared with the nematode inoculated control. In addition, T. harzianum markedly enhanced chlorophyll content and biomass production while suppressed the nematode reproduction. These findings indicate that soil application of T. harzianum represents an effective, environmentally sustainable, and economically viable approach for the management of root-knot disease and the improvement of chilli productivity under protected cultivation conditions.