Diseases of fruit plantation medicinal and aromatic crops (2+1)

Root rot disease

Brown root disease
Causal organism: Fomes lamaoensis (Murrill) Sacc. & Trott.
Symptoms

• The disease appears on the decaying slumps of jungle and shade trees that have been cut and left in the soil It is widely distributed in the tropics occurring in Java, Malaysia, Sri Lanka, Sumatra, East and West Africa.
• It also attacks a number of other trees like bread fruit, cacao, coffee, rubber, etc.
• The roots of the tea bush are encrusted with a mass of earth and small stones cemented to the root by the mycelium. When aged, the mycelium acquires a black covering, sometimes with a brown powdery outer layer.
• Between bark and the wood, there is usually a thin layer of white or brownish mycelium.
• The fructification is rarely formed on cultivated plants killed by this fungus.
• The disease spreads through root contacts.
• This is a faster killer than stump rot and more common on sandy soils than clayey soils.