Comparative Studies on Antagonism of Trichoderma Harzianum Strains Against Colletotrichum Capsici (Syd.) E.j. Butler & Bisby

Abstract

Chili (Capsicum annuum L.) is one of the world's most important spice crop. India is the world's largest producer, consumer and exporter of this crop. Chilli crop suffers from about more than 40 fungal diseases. Out of which Anthracnose of chilli is one of the major and devastating diseases and causes severe losses both in yield and quality as well as results in both pre- and post-harvest fruit decay with yield losses up to 50%. The pathogen is seed, soil and air borne. Trichoderma as a potential biocontrol agents of plant pathogenic fungi has been known for more than six decades. Trichoderma use mechanisms like competition, induction of resistance in plants, production of cell wall degrading enzymes, mycoparasitisms and production of secondary metabolites to control different pathogens. The present investigation was conducted to study the comparative antagonistic activity of Trichoderma harzianum strains against Colletotrichum capsici and their effect on plant growth of chilli under pot conditions. A comparative study were carried out between old lab maintained Trichoderma strains and re-isolated Trichoderma strains after 30th and 60th days of inoculation into soil. All the re-isolated Trichoderma strains exhibited greater antagonism than old lab maintained strains in vitro. IRRI 1 strain exhibited highest level of inhibition followed by SV 7 and SV 21. IRRI 1 strain of T. harzianum reduced the fruit rot incidence significantly. SV 7 strain was found to be the next best strain in terms of reducing the disease incidence in the crop. All the Trichoderma harzaianum strains were found to enhance the plant growth (Plant height, Plant fresh weight, Shoot length and Root length). Yield of chilli also enhanced significantly due to Trichoderma harzianum strains application. Seed application of Trichoderma is found more effective as compared to soil application in reducing the disease and promotion of plant growth as well. Out of six different media tested Potato dextrose agar medium was found to be most suitable for radial growth of Colletotrichum capsici. Overall, it was found that the reisolated strains exhibited greater antagonism than older one. Thus, the performance of the bio agent could be improved by introducing them into natural environment and these bioagent can be used in management of fruit rot disease and enhancement of plant growth and yield as well.