Diseases of Fruit Plantation Medicinal and Aromatic Crops

Fruit rot of Jack fruit

Causal organism: Rhizopus artocarpi
SYMPTOMS

• Young fruits & inflorescence are badly attacked by the fungus and only a fruits reach maturity. Female inflorescence and mature fruits are generally not infected.
• It is a soft rot disease causing dropping of a large no. of affected fruits.
• Initially the fungus appears as a greyish growth with abundant mycelia that gradually become dense forming a black growth.
• The fungus advances slowly until the whole fruit or entire inflorescence become rotten and drop.
Causal organism: Rhizopus oryzae, Rhizopus artocarpus, and Rhizopus stolonifer. No variety has been reported to have significant resistance to the disease.
Epidemiology

• Warm, humid, rainy conditions favour the development of rhizopus rot. Wind, rains and insects dislodge and spread the tiny fungal spores.
• When deposited on moist fruit surfaces, the fungal spores germinate and infective mycelia enter and grow into the tissues.
• The infection produces a layer of black spores on the fruit surface to start secondary cycle of infection and disease. Although wounds can predispose the fruit to infection, yet the unwounded flowers and young fruits are also susceptible.
• Rhizopus can survive on decaying plant litter or in the soil to initiate new infections.
Management
• Prune the tree to encourage good ventilation and reduce relative humidity in the canopy.
• Remove and destroy diseased fruits from trees and the ground. Also clean the decaying organic debris within and around the tree.
• Ensure that water does not stagnate around the root zone. Control weeds around the young trees.
• Intercrop jackfruit with trees which are not susceptible to Rhizopus infection. Keep ripe fruits away from contact with the soil or decaying organic material.
• Avoid bruising and wounding of the fruits. Wash fruits after harvest in clean water and dry them thoroughly before packing or transporting.
• Examine critically and remove the fruits showing disease symptoms.
• Avoid storing fruits in hot and poorly ventilated container after harvest.
• Chemical Control:
• Spraying trees with young fruits using capton (0.2%) or Bordeaux mixture (1.0%) or copper oxy chloride (025%) at interval of three weeks during the months of Jan – Feb & March is effective in controlling the disease.