Enhancing brinjal resilience to little leaf disease through bio-intensive management

Little leaf disease, caused by Candidatus Phytoplasma trifolii, is a major risk to brinjal cultivation, leading to reduced yield and quality. Traditional chemical control methods offer only temporary relief and pose environmental risks. This study aimed to develop a bio-intensive strategy for managing little leaf disease by identifying effective rhizobacterial isolates with plant growth-promoting traits. Among 100 isolates screened, Bacillus licheniformis (B 67) demonstrated the highest indole-3-acetic acid (IAA) activity, siderophore activity and phosphorus solubilisation, followed by isolate B 38. Pot culture experiments revealed that treatments involving seedling treatment and drenching with B. licheniformis (B 67) or Bacillus subtilis (Bbv 57), combined with need-based application of neem seed kernel extract (NSKE 5%), demonstrated significant reductions in disease incidence and improvements in plant health. Field trials validated the efficacy of an Integrated Pest and Disease Management (IPDM) module developed from the findings of pot culture studies. The module comprised seedling treatment with B. licheniformis (B 67) and B. subtilis, drenching with humic acid, foliar applications of ferrous sulphate and zinc sulphate and targeted chemical sprays. This approach achieved the lowest disease incidence and significantly improved yield compared to untreated controls. The study underscores the potential of bio-intensive management strategies integrating rhizobacteria, micronutrients and eco-friendly sprays to sustainably manage little leaf disease while enhancing crop resilience and productivity. These results provide evidence for environmentally safe and effective alternatives to chemical-based disease management in brinjal cultivation.