This document summarizes diseases that affect jackfruit crops. It describes 4 diseases - dieback caused by Botryodiplodia theobromae, rhizopus fruit rot caused by Rhizopus stolonifer and Rhizopus artocarpus, leaf spot caused by Phyllosticta artocarina, and pink disease caused by Botryobasidium salmonicolor & Corticium Salmonicolor. For each disease, it provides details on symptoms, causal organisms, epidemiology, and management recommendations. The document is authored by Dr. Siddu Lakshmi Prasanna from the Department of Plant Pathology.

1. Siddu Lakshmi Prasanna
Course No.: PATH 2.7.1.
Course Title: Diseases of Fruit, Plantation, Medicinal
and Aromatic crops
By
Dr. Siddu Lakshmi Prasanna
Ph. D (Agri.)
Dept. of Plant Pathology

2. Jack fruit
Sr.
No.
Disease Causal organism
1. Dieback Botryodiplodia theobromae
2. Rhizopus fruit
rot
Rhizopus stolonifer
Rhizopus artocarpus
Phytophthora palmivora
3. Leaf spot- Phyllosticta artocarina
4. Pink disease- Botryobasidium salmonicolor &
Corticium Salmonicolor
Siddu Lakshmi Prasanna

3. Die back
Causal organism: Botryodiplodia theobromae
SYMPTOMS:
• Discoloration & darkening of the bark from the tip.
• The dark area advances & young green twigs start withering first at the base &
then extending outwards along the veins of leaf edges.
• The affected leaves turn brown & their margins roll upwards at this stage.
• The twig or branches shrivels & falls there may be exudation of gum from
affected branches
Siddu Lakshmi Prasanna

4. • Such branches have also been found to be affected by shoot borers and
shot hole borers when split open.
• In early stages, epidermal and sub-epidermal cells of twigs are often
slightly shrivelled.
Siddu Lakshmi Prasanna

5. Etiology:
• Pycnidia are asexual fruiting body, up to 5mm in diameter.
• Conidia are asexual spores, thin walled at first and become thick walled,
septate mycelia is present.
Primary source of inoculum: Dormant mycelia in infected plant debris
Secondary source of inoculum: Soil and airborne conidia.
Epidemology:
Temperature at 25 -30° C, relative humidity (80- 85%), susceptible host.
Siddu Lakshmi Prasanna

6. Management:
• Pruning of infected twigs followed by spraying of carbendazim 0.1%
or thiophonate methyl 0.2 % or chlorothalonil 0.2% is recommended.
• Controlling shoot borer & shot hole borers by suitable insecticides is
also important in reducing die back disease
Siddu Lakshmi Prasanna

7. SYMPTOMS:
• The young fruits & infloresence are badly attacked by
the fungus & only a small percentage of the fruit reach
maturity.
• Female inflorescence & matured fruits are not usually
attacked.
• The disease is a soft rot, a large no. of the affected fruits
fall off early.
Fruit rots
Causal organism: Rhizopus artocarpus
Siddu Lakshmi Prasanna

8. • In the first stage of attack the fungus
appears as a grayish growth with
abundant mycelia which gradually
becomes dense forming a black
growth.
• The fungus gradually advances until the
whole fruit or the entire inflorescence
rots & falls off.
Siddu Lakshmi Prasanna

9. Causal organism:
• Three species of plant-pathogenic fungi of the genus Rhizopus can cause this
disease in the tropics:
• Rhizopus oryzae, Rhizopus artocarpus and Rhizopus stolonifer.
• No jackfruit varieties are reported to have significant resistance to the disease.
Primary source of inoculum: Mycelia in Infected plant and fruit debris
Secondary source of inoculum: Sporangiospores disperse through wind,
rain, insects
Siddu Lakshmi Prasanna

10. Epidemiology:
• Warm, humid, rainy conditions favor the development of rhizopus rot.
• Wind, rain, and insects dislodge and spread the tiny fungal spores.
• When deposited on moist fruit surfaces, the spores germinate and infective
mycelia grow into the tissues.
• The infection produces a layer of black spores on the fruit surface to start
secondary cycles of infection and disease. Although wounds can predispose the
fruit to infection, unwounded flowers and young fruit are also susceptible.
• Rhizopus can survive on decaying plant litter or in the soil to initiate new
infections.
Siddu Lakshmi Prasanna

11. Disease cycle
Siddu Lakshmi Prasanna

12. Management
• Prune the tree to encourage good ventilation and to reduce relative humidity in
the canopy.
• Remove and destroy diseased fruit from trees and the ground. Clean up
decaying organic debris within and around the tree.
• Ensure that water does not pond around the tree’s root zone. Control weeds
around young trees.
• Intercrop jackfruit with trees that are not susceptible to infection by
Rhizopus.
• Avoid wounding the fruit.
Siddu Lakshmi Prasanna

13. • Wash fruit after harvest in clean water and dry thoroughly before packing
or transporting.
• Do not pack fruit with symptoms, destroy them.
• Avoid storing fruit after harvest in hot, poorly ventilated containers.
• Spraying of the young fruits with capton 0.2% or Bordeaux mixture 1.0%
or copper oxychloride 0.25%.
• An interval of three weeks during the months of Jan – Feb & March is
effective in controlling the disease.
Siddu Lakshmi Prasanna