Manganese Toxicity—a Cause of the Death of Mango Trees in the Kosi Flood Affected Areas of Bihar

Large scale destruction of mango trees occurs in the Kosi-flood affected areas of north Bihar. Manganese contents of the suspended material in the Kosi water and the flood depositions at the affected orchard sites were unusually high and the affected plants accumulated much higher amounts of manganese in leaves, twigs and bark than normal healthy plants. A 800 ppm manganese concentration (a concentration similar to that in the suspended material of the Kosi-water) in solution culture caused in the plants manganese toxicity which was alleviated by 1200 ppm of iron. Destruction of mango trees in the Kosi-flood affected areas may have been caused by the toxicity of the excess of manganese in sediments carried and deposited by the floods.