Symptoms
Symptoms begin with yellowing in intercostal areas at the base of leaflets or leaf margin. The chlorosis expands to the whole leaf as the deficiency continues. The margin often remains green.
Eventually necrotic patches appear in the yellow areas which terminate as intercostal leaf scorch.
Symptoms are most severe in the oldest leaves, which have green veins and large areas of marginal and intercostal necrosis.
Causes
Severe magnesium deficiency.
Manganese deficiency is similar but here intercostal yellowing starts on younger leaves and the necrosis is usually in spots along the line of the veins.
Potatoes: 2-4 l/ha 1 week after 100% emergence and following petiole analysis during tuber bulking. For moderate to severe deficiency, repeat applications at 10-14 day intervals. Water rate: 200 l/ha.
Read more about YaraVita MAGFLO 300