In particular, it affects fruit colour, delays maturity, reduces juice content, and results in thick skins. Visual symptoms of P deficiency are not usually seen in New Zealand but the effects on fruit quality are common in most districts. These include low juice content, thick skins, and acid juice. Magnesium deficiency is particularly common in years of heavy crops. Symptoms include the yellowing of leaves with an inverted v of green tissue at the base of the leaf.
Manganese deficiency occurs in all citrus growing areas of New Zealand.
Symptoms include the development of an interveinal yellowing with a band of darker green along the midrib and veins. Zinc deficiency produces symptoms which are similar to Mn deficiency but the interveinal yellowing is less blotchy and more clearly defined. In extreme cases leaves can be small, narrow, pointed and rosetted in the classical little leaf symptom. Zinc deficiency can also affect fruit shape. Manganese and Zn deficiency often occur together and can be corrected together or singly.