Burkholderia plantarii

Systematic position and nature of the pathogen: Burkholderia plantarii belongs to the Bacteria domain, Proteobacteria phylum, and Burkholderiaceae family. It is a Gram-negative, aerobic, rod-shaped, and motile bacterium. This microorganism is a significant phytopathogen that primarily affects various agricultural crops, with rice being the most susceptible host.

Diseases and susceptible crops: The primary disease caused by this pathogen is bacterial seedling blight of rice. The infection typically targets seedlings during their early developmental stages. Furthermore, B. plantarii can colonize seeds and stems, resulting in significant reductions in crop yield and detrimental effects on the overall quality of the harvested grain.

Biology and life cycle: The bacterium survives in infected rice seeds, soil, and crop residues. Throughout its lifecycle, it produces a specific toxin known as a tropolone compound, which inhibits root elongation and induces necrotic lesions in the plant tissues. Dissemination occurs primarily through contaminated seeds, irrigation water, and the movement of agricultural tools or machinery across fields.

Conditions for development and harmfulness: Optimal conditions for the proliferation of Burkholderia plantarii include high humidity and moderately warm temperatures (25–30°C). Its harmfulness is particularly evident during the early growth phase, often leading to mass seedling death and sparse field density. In later stages, the infection manifests as lodging and stunted growth of the rice panicles.

Protection and control measures: Effective management requires an integrated approach combining agronomic and chemical strategies. Key practices include:

• Utilizing certified disease-free seeds for planting.
• Implementing seed disinfection techniques or chemical seed treatments prior to sowing.
• Maintaining proper crop rotation and removing crop debris from the fields.
• Regulating water levels in rice paddies and monitoring water quality for pathogen presence.