Bacterial disease - Erwinia head rot or Soft rot or Snap off or Tip Over

BACTERIAL DISEASE - Erwinia head rot 

(Soft rot or Snap off or Tip over):

Symptoms:

This bacterial attack is normally construed by farmers as fungal attack by mistake. This attack is known by different names like Erwinia attack, Head rot, Soft rot, Snap off and Tip Over. Tissue culture raised Banana plants are prone to this bacterial attack.

This disease is caused by soil borne bacteria Erwinia carotovora that enters the young banana plants through wounds that may be sustained at roots at the time of planting. They are also carried in to the plant through decaying outer sheaths of the rhizome that may be occurred due to some fungal infection.

Underground stem of young plants get infected by this bacterium, leading to extensive rotting and emitting of odour.  Older plants show rotting at the collar region (the region where stem originates from rhizome) and leaf bases. The affected part will become so weak that it will snap off the corm easily even for a normal wind force. In severe cases, pseudostem base becomes swollen and splits. Affected portion looks yellowish brown with a definite brown margin. Disease also spreads to the daughter suckers of the clump.

Observed commonly during hot summer months and during rainy season too after 3rd to 5th months of planting in the field. The pathogen is soil borne and spreads through water. Rotting of collar region leads to drying of outer and inner leaves. If affected plants are pulled out it comes out from the collar leaving the corm that is why called as 'Snap off' or 'Tip over'.

Erwinia Soft rot / tip over bacterial disease attack on Banana

 

Erwinia Soft rot bacterial disease attack (early stage) on Banana raised in 'Jiffy' pots.

Control:

1. During hot summer periods tender roots of Tissue Culture plants may get damaged (burns/scorching) due to excessive heat build up of the surface soil resulting in decaying of the affected root portion. The soil borne bacterium 'Erwinia' enters the plant through the above wounds in the roots. So, this bacterial attack on Tissue Culture plants can be effectively controlled by maintaining sufficient moisture around the root zone of the plant during (hot summer) initial months to prevent heat injury to tender roots.
2. Drip irrigation may be done preferably during early morning or late evening hours and avoid irrigating the plant during hot noon.
3. Sudden rainfall during hot summer may also results in severe bacterial attack on plants. So always maintain moisture around root zone to effectively prevent the attack which is known to severely hurt the farmer economically.
4. Provide good drainage wherever water stagnation occurs in the field.  
5. In case of tissue culture plants, one week before planting prepare a solution of 400 gm of Fytolan (Blue copper or Copper oxy Chloride - COC) + Streptomycin with Tetracycline ( Streptomil, Crocin ) which is available in 6gm pocket in the market, total 42 gm i.e 7 pockets + 200 litres of water and drench the polythene bags (i.e., all the Poly-bag plants) in the nursery. For Tissue culture plants that are already planted, take care to apply the above solution very close to the plant so that the root ball gets drenched fully. This application prevents not only 'Erwinia' but also any other fungal root infection effectively. Please note that Streptomycin acts well in conjunction with COC.
6. Drenching the soil around the plant with 0.1% Emisan in 1st and 3rd month.
7. Spray 0.05% Streptocycline on the plants at weekly interval for 2 to 3 weeks soon after the incidence.
8. For very severe attack, drench the soil around the plant with 2% Bleaching powder (20gms /lt) solution in water, weekly for 2 weeks.
9. For a novel method for effective control of 'Erwinia soft rot' in Banana plants over 3 months of age, please refer this link:'Pseudostem Injector'.

Regards,
A.Vishnu Sankar