bakanae

Bakanae, meaning fooling seedling in Japanese, is a disease of rice (Oryza sativa) characterized by abnormal seedling elongation and growth. It is commonly called fooling seedling disease in English literature and is a notable problem in rice nurseries and early field establishment.

The disease is caused primarily by fungi in the Fusarium fujikuroi species complex. The pathogen infects seeds and young seedlings and produces gibberellins, plant hormones that stimulate excessive vertical growth. This hormonal imbalance yields tall, thin, and etiolate seedlings that are weak and prone to lodging.

Symptoms include elongated, spindly seedlings with long internodes, pale green leaves, and a weak root system. Affected plants may lodge or die before transplanting, and widespread infections can lead to significant yield losses. Infection is often seed-borne, enabling spread through planting material, though the fungus can also persist in residue and soil under suitable conditions.

Bakanae is most common in warm, humid climates typical of rice-growing regions. Management focuses on preventing infection and reducing inoculum. Key strategies include using certified disease-free seed, hot-water treatment of seed (approximately 50 C for 20–25 minutes), and seed treatments with fungicides effective against Fusarium. Sanitation to remove infected plants, strict seed hygiene, and crop rotation or diversification can help reduce risk. Where available, selecting tolerant or less susceptible varieties can also lessen impact. Integrated approaches that combine seed sanitation, proper planting practices, and timely field monitoring are used to minimize losses from bakanae.