Key symptoms of YCSKey symptoms of YCS
- Overall the crop generally looks quite orange-yellow, with the yellowing extending into the youngest leaves in the worst affected crops.
- Young leaves show faint yellowing at the tip. This progresses to a stronger yellowing generally to one side of the leaf and towards the leaf tip.
- Leaves 5 or 6 generally show uneven coarse mottling, with areas of uneven green and yellow tissue developing.
- Unlike typical viral or nutrient deficiency symptoms, this symptom is uneven, and looks more like a stress condition or herbicide effect.
- It extends right down the leaf blade.
- The midrib remains white and is the last part to turn yellow.
- Leaves in the lower canopy are more uniformly yellow, showing areas of brown-black necrotic spots.
- Leaf tips and some margins begin to die, with older leaves senescing earlier.
- Once affected, yellow leaves do not recover. In extreme cases, cane stalks may become thin and rubbery and root health is compromised.
- Symptoms may also ‘come and go’ in waves.