Fusarium paspali

The fungus Fusarium paspali is a specialized pathogen recognized for its ability to infect various species of grasses. As a member of the diverse Fusarium genus, it primarily targets the reproductive structures of plants, leading to significant physiological disturbances. It is classified as a causal agent of fusarium wilt and spikelet rot in susceptible grass hosts.

The primary host range includes Paspalum species and other related grasses. While it is often studied in wild grasses, its economic impact is most pronounced in forage production, seed fields, and amenity turf. In these settings, the pathogen disrupts the normal development of the inflorescence, directly impacting reproductive success and vegetative vigor.

Symptoms of Fusarium paspali infection typically appear on the spikelets or the rachis of the grass. The most common sign is the development of a fluffy, mycelial growth ranging in color from white to soft pink. As the infection progresses, affected tissues become discolored, and the developing seeds may wither or fail to fill, resulting in empty or infected spikelets.

Development and spread are heavily influenced by environmental moisture. High relative humidity and frequent rainfall during the flowering stage create ideal conditions for conidial germination and host colonization. The pathogen is disseminated primarily through wind-borne spores and splashes of rain, which transport the fungus from crop residues to healthy, vulnerable flowering parts.

The harm caused by this disease extends beyond simple biomass reduction. Infected plants often show poor seed viability, leading to sparse stands in the following season. Furthermore, the presence of mycotoxins in infected forage poses significant health risks to grazing animals, making the detection and control of this pathogen essential for safe agricultural practices.

Integrated disease management strategies include:

• Removal and destruction of heavily infected plant debris post-harvest.
• Application of systemic fungicides during the early stages of flowering.
• Use of certified, clean seed lots treated with appropriate seed dressings.
• Management of irrigation to reduce leaf wetness duration during the critical flowering period.