Plant Pathology: Extension: Plant Disease Library

Curvularia

Important diseases: Curvularia blight of turf, Fading out of turf, Curvularia leaf spot of Oyster plant and Hibiscus, Grain mold of sorghum, Kernel smudge of wheat, and Curvularia leaf spot of corn

Curvularia is mainly an opportunistic leaf spot fungus and a weak pathogen that survives mostly as a saprophyte. It is easily isolated from dead turf (thatch) and other weakened and dead plant tissue. It causes leaf spots on grasses as well as storage molds of grains.

 
 

Leaf spots are similar to those caused by Helminthosporium, in some turf such as bermudagrass leaf infection is initially a dappled yellow with the later forming leaf spot having a reddish brown margin and a grey to straw colored center (depending on the turf involved). Overall appearance of infected turf is thin, ragged and yellowing. Lesions at the base of leaf blades can cause wilting and death of the leaves. Thatch and other dead plant material can support growth of Curvularia often visible to the naked eye as a blackish dust or mold. Stored grain infected with Curvularia often has a blackened, smudged appearance.


Conidiophores of the fungus are brown, mostly simple, bearing conidia near the apex. Conidia are boomerang-shaped to more or less fusiform (spindle-shaped) and typically bent. They are dark with usually 3 vertical septations. The central cell is often enlarged.