Biological Control of Phytophthora drechsleri f. sp. cajani causing Stem Blight of Pigeonpea

Abstract

Stem blight of pigeonpea (Cajanus Cajan L.), caused by Phytophthora drechsleri f. sp. cajani, is major disease limiting crop productivity. This study assessed the potential of selected fungal and bacterial biocontrol agents to suppress the pathogen under in vitro and pot culture conditions. Trichoderma asperellum and T. harzianum exhibited the strongest inhibitory effects on pathogen growth through dual antagonism test. In addition, bacterial isolates of Bacillus and Pseudomonas demonstrated reliable antagonistic activity. Pot culture experiments confirmed that treated plants experienced lower disease severity and improved growth compared to inoculated controls. These findings suggest that combined application of fungal and bacterial bioagents provides an effective and environmentally friendly approach for managing stem blight in pigeonpea. Future work should focus on multilocation field testing, molecular profiling of the most effective strains and development of stable formulations to optimize sustainable disease management.