Fusarium seed rot

Fusarium seed rot is caused by a complex of soil-borne fungi of the genus Fusarium, such as Gibberella acuminata. This fungal disease targets seeds, invading the internal tissues and embryos, which prevents normal germination and often leads to pre-emergence or post-emergence damping-off.

The pathogen affects a wide array of crops, with soybeans being particularly susceptible. The infection reduces seed vigor and germination rates, threatening the overall crop density and stand establishment at the very beginning of the growing season.

Symptoms include the appearance of white, pink, or reddish mycelial growth on the seed coat. Infected soybean seeds often show signs of discoloration or decay, and if they germinate, the radicles may appear brown, water-soaked, and necrotic, leading to the rapid collapse of the seedlings.

Development and spread are favored by cool, wet soil conditions during the planting phase. The pathogen survives in the soil on crop residues or as dormant chlamydospores, and it is frequently introduced into new fields through the use of infected, non-treated seeds.

The economic impact is significant due to reduced yields and the potential for crop failure in high-pressure years. Prevention strategies focus on utilizing certified, disease-free seed, applying systemic fungicide seed treatments, and implementing crop rotation practices to reduce inoculum levels in the soil.