Field efficacy of Trichoderma viride, Pseudomonas fluorescens, and consortia of microbial agents against tomato late blight, Phytophthora infestans (Mont.) de Bary in Indo-Gangetic Plain of Bihar

Late blight of tomato, caused by Phytophthora infestans, leads to substantial yield losses and significant reduction in crop production, if not managed effectively. Management of tomato late blight largely relies on chemical treatments, which poses a huge risk to the environment. Assuming that biological control is an alternative for late blight management, Trichoderma viride (Tv), Pseudomonas fluorescens (Pf), Arka Microbial Consortium (Bc₁) and PUSA Sampoorn Microbial Consortium (Bc₂) in different combinations were evaluated in present investigation. Among all tested combinations of biocontrol agents, Pf + Bc₁ + Tv + Bc₂ was the most effective with lowest disease incidence (7.41 and 8.85 %) followed by Tv + Bc₂ (10.01 and 11.52 %) during 2022-23 and 2023–24, respectively. During both years, biocontrol agents lowered the disease index by 33–72 % as compared to the control. Furthermore, application of Pf + Bc₁ + Tv + Bc₂ resulted in a marked reduction in the area under disease progress curve (71.7 and 73.4 %) and enhanced the tomato yield (32.9 and 35.5 %) significantly over control. Findings from the present study indicate that the integrated application of T. viride, P. fluorescens and microbial Consortia provides a highly effective and cost-efficient biocontrol strategy for managing late blight in tomato crops. This approach combines multiple beneficial microorganisms that work synergistically to suppress the disease, making it a sustainable and economically viable option for tomato growers.