Disease : Bacterial Wilt or Moko Wilt

This bacterial disease is now noticed in all banana growing tracts of the State.

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Symptoms

  • Widely distributed bacterial disease of banana .
  • Affected plants show rapid wilting and youngest leaves collapse.(Image1)
  • Later, these symptoms progress towards the older leaves
  • In Cavendish varieties, the lower leaves develop a yellowish tinge which quickly spreads all over the leaves. Leaves acquire a tingy whitish-yellow appearance, become dry, flaccid and readily droop around the pseudostem
  • Petiole breaks at its junction with lamina or pseudostem.
  • If the diseased suckers are planted, terminal leaf becomes necrotic and the plant dies.
  • Infected young sword suckers show wilting and blackening.
  • Vascular discolouration ranging from pale yellow to dark brown or bluish black in the form of a ring is seen at the central part of the pseudostem, when it is cut transversely.(Image2)
  • Reddish tinge observed in case of Panama wilt is usually absent.
  • Slimy drops of bacterial ooze which is greyish brown in colour appears at the transverse cut end of the pseudostem.(Image3).
  • When fruit bunch is produced, the fingers appear distorted and turn yellow resulting in premature ripening of fruits.(Image4)
  • The pulp turns into a very characteristic dark brown colour.
  • Blackened necrotic male buds with infection moving up the fruit stalk is another characteristic symptom.

Procedure for Observation

Inspect the field at regular intervals and look for the symptom of bacterial diseases. Confirm by ooze test.

ETL

Mere presence

Epidemiology

The bacterium is soil borne and can survive in soil for 12-68 months. Infected suckers are the major source of inoculum. The bacterium is transmitted through tools. Insect pests help to disseminate the bacteria oozing out through the wounds. Similarly, the pollinating insects disseminate the oozing out through male flowers. The bacterium has a very wide host range infecting a large number of cultivated plants and weed hosts. Heliconias are susceptible to the banana strain of the pathogen and many of the members can serve as symptomless carriers. All varieties of commercially cultivated bananas are susceptible to the disease.

Control Measures