- Typical damage is degenerated tissue along the inner margins of emerging leaves.
- As the leaves expand yellow damaged areas become conspicuously visible.
- Tillering is reduced and maturity may be delayed.
- Whorl maggot attacks fields with standing water.Damage occurs from seedling to maximum tillering stage.
Randomly mark 4 one meter sq.plots from 0.4 Ha.Assess the total number of hills showing symptoms from 4 meter square.Take average.