In vitro Assessment of Biocontrol Agents and Essential Oils for Sustainable Management of Banded Leaf and Sheath Blight in Maize

Abstract

Maize (Zea mays L.) is a vital cereal crop globally and in India, where its productivity is often limited by biotic stresses such as banded leaf and sheath blight (BLSB), caused by Rhizoctonia solani f. sp. sasakii. In this study, BLSB-infected maize samples were collected from Kalyani, West Bengal, and the pathogen was isolated, morphologically and molecularly characterized. The Rs-01 isolate exhibited typical Rhizoctonia morphology and pathogenicity was confirmed through Koch’s postulates. Molecular identification using ITS sequencing further validated the identity of the pathogen, and a phylogenetic tree analysis placed the isolate firmly within the R. solani clade. In vitro evaluation of six fungal biocontrol agents revealed that Trichoderma harzianum (Th-02) showed the highest inhibition (92.59%) of pathogen growth, followed by other Trichoderma isolates. Additionally, the antifungal efficacy of eight essential oils was tested using the poison food technique. Tea tree, garlic, lemongrass, turmeric, and tulsi oils demonstrated complete (100%) inhibition of R. solani growth, while neem, aloe vera, and moringa oils exhibited comparatively lower antifungal activity. The findings suggest that selected Trichoderma isolates and specific essential oils hold strong potential for the eco-friendly management of BLSB in maize.