Recognize the problem
Jackfruit is a popular garden
species prized for its edible flowers, fruit, and seeds for fresh consumption
or cooking. Rhizopus rot is a common fungal disease of jackfruit flowers and
fruit in the tropics. As a result of this disease, a big
portion of the national revenue can be lost.
At first, soft, watery, brown
spots develop on the flowers and fruit. Subsequently, a powdery, fuzzy-looking
mass of black spores and white fungal mycelia covers the jackfruit surface. The pathogen
engulfs the young fruit, resulting in the characteristic black, rotten,
shrunken, and sometimes mummified fruit remains. Fruit symptoms can appear on
the tree or can develop on fruit in storage or transit. Warm, humid, rainy
conditions favour the development of soft rot. Wind, rain, and insects dislodge
and spread the tiny fungal spores. 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. Rot is more likely to occur in high-rainfall areas or during and
after stormy periods. When warm, humid, wet weather coincides with the
flowering and fruiting season, Rhizopus rot can cause total loss of fruit in
tree to encourage good ventilation and to reduce relative humidity in the
- Remove and
destroy diseased fruit from trees and the ground. Clear up decaying
organic debris within and around the tree. Water
stagnation at root zone should be avoided.
jackfruit with trees that are not susceptible to infection by Rhizopus
storing fruit after harvest in hot, poorly ventilated containers
fruit setting or 10 days after fruit setting, spray with carbendazim e.g. Bavistin, or mancozeb e.g. Indofil M-45 @
2 gm/L water, 2-3 times at 10-day intervals
If spraying after flowering, spray with tebuconazole e.g. Folicur @ 0.05%, or metalaxyl + mancozeb (e.g. Ridomil MZ-75)
or Indofil M-45 @ 2.5gm/L water, 3 times at 15-day intervals
When using a pesticide, always wear protective clothing and follow the instructions on the product label, such as dosage, timing of application, and pre-harvest interval.