Manganese deficiency is first apparent on young growth as light green areas that turn yellow or mottling laterally along the leaf margins. The discoloration goes from light green to white while veins remain green. The leaves become bronze and then die. Deficiency is often seen on non-acid soils, or soils over 6.8 pH. Managese is usually available in acid soils, where it can reach toxic levels. Gray speck disease and halo blight are actually manganese deficiencies.
Gray speck is gray brown or dead spots on the leaf.
Manganese levels in plants Excessively high calcium and phosphorus can require more manganese. Concentration of manganese in crops and forages is dependent on soil factors, plant species, stage of maturity, yield, crop management, climate and soil pH. Manganese is highly concentrated in outer layers of grains. Restoring manganese to deficient plants Spray with manganese sulfate precipitated with lime. Manganese oxide spray less residue on the leaves. It has been investigated in relation to epilepsy, and people suffering from this disorder have depressed amounts of manganese in their bloodstreams.