Symptoms appear on the older leaves.  Older leaves may fall off, or they develop a triangular arrowhead at the base of the leaf, near the stalk.  Reduction in growth, marginal chlorosis, interveinal chlorotis (yellow between the veins) in some species.  Eventually the whole leaf becomes yellow.

Foliar spray of Magnesium sulphate @ 0.5%(5g MgSo4 dissolved in 1 lit of water) in the interval of 15 days on the foliage till the symptoms disappear.