The older leaves are pale green to yellow and abscise. The life of a leaf can be shortened from 1-3 years to 6 months. The leaf veins have a clear colour tending to white.
Made worst by
Low or high pH soils. Sandy or light soils (leaching.) Low organic matter. Drought conditions. High rainfall (leaching) or heavy irrigation. Addition or high levels of non-decomposed organic matter/manure (eg straw). Fast growing crops.
Foliage lusher and greener. Shoot growth vigour increased. Fruit set/crop load increased. Yield is increased. Juice quantity and quality improved (acidity and soluble solids increased).
Nitrogen deficiency Sulfur deficiency causes similar symptoms, but it begins at the younger leaves and the veins are usually green.