Khuskia

The disease is caused by the fungus Khuskia oryzae (anamorph Nigrospora oryzae). It belongs to the group of ascomycete fungi and acts primarily as a facultative parasite, meaning it can survive on decaying organic matter but readily infects living plant tissues under stress.

The primary host for this pathogen is rice, though it is also known to infect maize, sorghum, and several other cereal species. It often impacts plants during the reproductive stages, targeting tissues that are nearing maturity or those damaged by environmental factors.

Symptoms are characterized by the appearance of dark, necrotic spots on leaves and stems. A distinct sign of infection is the presence of black, sooty fungal masses (spore clusters) on the panicles or grains, which eventually leads to grain discoloration and shriveling.

Favorable conditions for the development and spread of Khuskia oryzae include high atmospheric humidity, frequent rainfall, and warm temperatures. The spores are primarily wind-dispersed and water-splashed, allowing for rapid movement between fields during the growing season.

The economic impact of this disease includes significant yield losses and poor grain quality, making it unsuitable for commercial processing. To mitigate these risks, farmers should focus on cultural practices such as deep plowing to bury crop residues, ensuring adequate field drainage, and utilizing resistant cultivars whenever possible.