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

Canker

Causal organism: Ceuthospora phyllosticta
Symptom

• Elliptic black spots are formed on twigs.
• Infected areas become flattened and depressed with raised edge.
• Later the bark becomes dry which cracks and the wood below show abnormal, dark brown to black discoloration.
• Twigs beyond the cankerous spots turn dry and in severe cases the infected trees become dead.

Mode of spread and survival

Pathogen can survive on the cankerous growth of leaves, stem or fruits. In the warm rainy season bacteria ooze out from cankers and spread through water splash and air. It enters the through stomata and wounds on the plants.


Life cycle

The bacterial spores present in the cankers ooze out when conditions are congenial for them and become water splash borne or air borne. When they come in contact with the host plant surface, they enter through stomata or injuries, multiply inside the plant, cause infection, and develop symptoms like cankerous growth on the surface and thus repeat the life cycle.