A Comparative Study of Using Seaweed Extracts and Biocontrol Agents for an Eco-friendly Management of Chilli Fruit Rot Caused by Colletotrichum capsici
S. Jayasurya *
Department of Genetics and Plant Breeding, Faculty of Agriculture, Annamalai University, Chidambaram – 608 002, Tamil Nadu, India.
A. Kamaraj
Department of Genetics and Plant Breeding, Faculty of Agriculture, Annamalai University, Chidambaram – 608 002, Tamil Nadu, India and Department of Genetics and Plant Breeding, Dr. MS Swaminathan Agricultural college & Research Institute, Tamil Nadu Agricultural University, Eachangottai, Thanjavur – 614 902, Tamil Nadu, India.
*Author to whom correspondence should be addressed.
Abstract
Chilli (Capsicum annuum L.) production is severely affected by anthracnose or fruit rot caused by Colletotrichum capsici, leading to substantial yield and quality losses. The present investigation evaluated the antifungal potential of selected seaweed extracts and biocontrol agents against C. capsici (Cc03) under in vitro conditions, along with their influence on seed germination and seedling vigour of chilli cv. K2. Aqueous extracts of five seaweed species were assessed using the poisoned food technique, while the antagonistic activity of microbial biocontrol agents was examined through the dual culture method. The growth-promoting effects of both seaweed extracts and biocontrol agents were evaluated using the standard roll towel method. Among the seaweed extracts, Sargassum wightii at 15 % concentration exhibited the maximum inhibition of C. capsici (Cc03) mycelial growth (77.61%) and significantly enhanced germination, seedling growth and vigour index. Among the biocontrol agents, Trichoderma harzianum (Th4) showed the highest antagonistic activity against the pathogen with 88.17 % inhibition and also recorded the maximum improvement in seed germination and seedling vigour, followed by Bacillus subtilis (Bs9). Overall, the results highlight the dual role of seaweed extracts and biocontrol agents in suppressing C. capsici (Cc03) and promoting early seedling growth, indicating their potential as eco-friendly and sustainable alternatives to chemical fungicides for the management of chilli fruit rot.
Keywords: Capsicum annuum, Colletotrichum capsici (Cc03), seaweed extracts, biocontrol agents, seedling vigour