Yellowing of Old Sugarcane Leaves and Crop Nutrition

If the sugarcane leaves – particularly older leaves - become light green to yellow in color and plant growth is reduced, the plant may suffer from an nitrogendeficiency. Leaf tips may become necrotic and the stalks, thin and stunted with reduced lengths between internodes.

Low nitrogen supply also increases the risk of an early switch from vegetative to generative growth causing development of unwanted flower panicles.

Early symptoms of a magnesiumdeficiency includes the appearance of chlorotic spots or yellow mottling of the leaf. Older leaves are more commonly affected with younger leaves often remaining green.

More classic, later stage symptoms are when these lesions merge to produce an orange/brown 'freckling'. Stalks may also have an internal browning.

Magnesium and calcium deficiencies may occur at the same time particularly on more at risk acid soils. Take care not to confuse these symptoms with those of rust diseases.

If in doubt whether it is a nutrition deficiency or disease, please assess through leaf analysis.