Diseases of Fruit Plantation Medicinal and Aromatic Crops

Branch canker

Causal organism: Macrophoma theicola Fetch.

• This is a disease that infects stem and produces characteristic cankered appearance.
• The disease appears during early part of the monsoon as small, slightly sunken, oval patches on the bark of young branches.
• These patches grow in the cambium, spreading rapidly between bark and the wood.
• The barks above the infected cambium quickly dies, turns black and fall.
• The black patches of dead bark crumbles off and the unaffected white wood underneath is exposed.
• In minor attacks, the infected patches are completely callused within a few months and after one or two only a sight scar remains.
• During the attack, the pycnidia or small fruiting bodies are produced under the bark which is covered over by callus.
• Where the callus formation is incomplete, spores from these pycnidia may give rise to subsequent attacks.
• Repeated attack of stems result in encircling the stem and finally killing them out. Prolonged drought condition renders the bark susceptible to Macrophoma.