Diseases of Fruit Plantation Medicinal and Aromatic Crops

Stem canker

Symptoms

• Infected twigs show wilting and death.
• Cracks and lesions are formed along the stem, arresting translocation of nutrients.
• Infected fruits turn dark brown to black and resulting in die-back symptoms.
• Fruit rotting takes place, blighting of leaves to enlargement
• Perithecia is glabrous with a fleshy wall. Ascospores are hyaline, narrow, ellipsoid and one celled.
• Conidia are single celled, ovoid with a rough wall and measure 20 to 26 x 9 to 12 µm. Pycnidia are formed in stroma on the stems and fruits.

Mode of spread and survival

• The pathogen remains in the infected tissues beneath the bark and become active under favorable conditions.
Management

• In severe infection, the disease can be controlled by removal and destruction of the infected stem.
• In mild infection, pruning of infected stem and branches is done and the cut-ends are painted with Bordeaux paste (1 part copper sulphate and 2 parts each of lime and linseed oil) or Chaubatia paste (copper carbonate - 800 g, red lead - 800 g and linseed oil - 1 litre).
• Spraying the trees with copper oxychloride (0.2 per cent) after pruning reduces canker incidence.