What it does
When plants receive too much nitrogen, they become more attractive to insects and diseases. It can also cause excessive growth and reduce the strength of the stems.
Why and where it occurs
The disease can occur in areas with high relative humidity (>90%) and temperature ranging from 25 to 35 ºC.
Rain and high humidity, and soils with high nitrogen content also favors disease development. Wind can spread the fungal spores from plant to plant.
False smut is visible only after panicle exsertion. It can infect the plant during flowering stage.
How to identify
Check for presence of velvety smut balls on spikelets.
Plants infected with false smut have individual rice grain transformed into a mass of spore balls. These spore balls are initially orange, and then turn greenish black when mature.
In most cases, not all spikelets of a panicle are affected, but spikelets neighboring smut balls are often unfilled.
Click on images to enlarge
How to manage
- Keep the field clean
- Remove infected seeds, panicles, and plant debris after harvest
- Cultivate unflooded rice (e.g., furrow irrigation) to reduce the disease
- Where possible perform conservation tillage and continuous rice cropping
- Use moderate rates of nitrogen
- Use certified seeds. Resistant varieties have been reported.
- Treat seeds at 52 C for 10 mins
Learn more
View full fact sheet: False smut on IRRI Rice Knowledge Bank