Manganese (Mn) deficiency is a plant disorder that is often confused with, and occurs with, iron deficiency. Most common in poorly drained soils, also where organic matter levels are high. Manganese may be unavailable to plants where pH is high.
Affected plants include onion, apple, peas, French beans , cherry and raspberry, and symptoms include yellowing of leaves with smallest leaf veins remaining green to produce a ‘chequered’ effect. The plant may seem to grow away from the problem so that younger
leaves may appear to be unaffected. Brown spots may appear on leaf surfaces, and severely affected leaves turn brown and wither.
Prevention can be achieved by improving soil structure. Do not over-lime.
Other physiological plant disorders include;