Major Banana Diseases and Their Management Practices

Crop: Banana

Scientific Name: Musa sp,
Family: Musaceae

1.Anthracnose: Gloeosporium musarum

Symptom:

• At the initial stage, small, circular, black spots develop on the affected fruits. Then these spots enlarge in size, turn to brown colour .
• The skin of the fruit turns black and shrivels and becomes covered with characteristic pink acervuli. Finally the whole finger is affected. Later the disease spreads and affects the whole bunch.
• The disease results in premature ripening and shriveling of the fruits which are covered with pink spore masses.
• Occurrence of black lesions on the pedicel causes withering of the pedicel and dropping of the fingers from the hands.
• Sometimes the main stalk of the bunch may become diseased. Infected fruits become black and rotten.
• The disease is favoured by high atmospheric temperature and humidity, wounds and brusies caused in the fruit and susceptibility of the variety.

MANAGEMENT:

• Avoid damage to fruits at harvest and transit.
• Burn the infected materials
• Proper field sanitation
• Keep the field free of weeds and provide good drainage.
• Fruit should be free from infection and as possible before it is transported, stored and ripened.
• Banana bunches should be harvested at correct stage of maturity.
• Proper fertilization prevents the infection.

2.Banana Bract Virus

Symptom:

• The disease is characterized by the presence of spindle shaped pinkish to reddish streaks on pseudostem, midrib and peduncle.
• Typical mosaic and spindle shaped mild mosaic streaks on bracts, peduncle and fingers also observed.
• Suckers exhibit unusual reddish brown streaks at emergence and separation of leaf sheath from central axis.
• Clustering of leaves at crown with a travelers palm appearance, elongated peduncle and half filled hands are its characteristic symptom.
• The virus is transmitted through aphid vectors. The virus is primarily spread through infected suckers. In the field, aphids vectors such as Aphis goosypii, and Rhopalosiphum maidis transmits the disease.

MANAGEMENT:

• The diseased plants should be removed as and when noticed to avoid the spread of the disease.
• Disease free planting materials should be used for new planting.
• The banana gardens should be kept free from weeds.
• Weeds in the nearby areas should be removed as the virus survives in them in off-season.
• Early detection by regular inspection of planting and eradication of diseased plants from the field as soon as they are noticed.
• Control of insect vector by spraying Phosphomidon at 1 ml per litre or Methyl Demeton at 2 ml per litre .
• For effective control of aphids we can use bio pesticides like Dr.Eliminator 250ml/acre.

3.Bunchy Top:Banana bunchy top virus

Symptom:

• Initially, dark green streaks appears in the veins of lower portion of the leaf midrib and the leaf stem.
• They appear to be “bunched” at the top of the plant, the symptom for which this disease is named.
• Severely infected banana plants usually will not fruit, but if fruit is produced, the banana hands and fingers are likely to be distorted and twisted. 
• It is transmitted by infected suckers and banana aphid.

MANAGEMENT:

• Use virus free planting materials.
• Remove and rouging of infected banana plants.
• Maintain clean, weed free field for early detection of infested suckers.
• The plants should be injected with 4 ml of Fernoxone  solution(50g in 400 ml of water).
• For effective control of aphids we can use bio pesticides like Dr.Eliminator 250ml/acre.

4.Yellow sigatoka:Mycospharella musicola

Symptom:

• Leaves show ellipthical spots where the centre of these spots turns to light grey colour surrounded by yellow halo.
• The spots often coalesce to form large irregular patches of dried tissue.
• Rapid drying and defoliation of leaves are the characteristic feature of this disease.

MANAGEMENT:

• Removal and destruction of affected leaves.
• Keep the banana field as weed free and remove the suckers timely.
• Avoid planting at close spacing.
• Provide proper drainage and avoid water logging in the fields which favours infection.
• Spray   3 times with Carbendazim 0.1 per cent or Propicanozole 0.1 % or Mancozeb 0.25% and teepol (sticking agent) at 10-15 days interval, as the disease starting from initial appearance of leaf specks .

5.Erwinia rot: Erwinia carotovora sub sp.  carovora

Symptom:

• This disease is more pronounced on young suckers leading to rotting and emitting of foul odour.
• Roting of crown region is a characteristic symptom followed by epinasty of leaves, which dry out suddenly.
• If affected plants are pulled out it comes out from the crown region leaving the corm with their roots in the soil.
• Splitting of pseudostem is common in late stage of infection in cultivars Robusta, Grand Naine and Thella Chakkerakeli.
• When affected plants are cut open at collar region yellowish to reddish ooze is seen.
• This soft rotting may spread radially towards growing point through the cortical tissues. The rotten corm emits foul smell.
• The disease can be spread by infected plant debris, plant wounds and injuries. Hot and damp weather with plenty  of rainfall  trigger the disease to occur. Water is required for the bacteria to invade into the plant.

MANAGEMENT:

• Good drainage and soil conditioning can control the disease to some extent.
• Plant disease free suckers.
• Remove infected plants immediately.
• Remove plant residues after harvest.
• Dip suckers in copper oxychloride (40g/10l)+ streptocycline (3g/10lit) for 30 min before planting.

6.Infection chlorosis mosiac disease:

Symptom:

• The disease is characterized by the presence of typical mosaic-like or discontinuous linear streaking in bands extending from margin to midrib.
• Rolling of leaf margins, twisting and bunching of leaves at the crown and a rigid erectness in newly emerged leaves.
• The presence of dead or drying suckers is noticed in advanced cases referred as heart rot resulting from rotting of heart leaf and central portion of pseudostem.
• Primarily infected banana plants develop severe mosaic symptoms in young growth showing broadly streaked chlorotic or yellowish green bands and patches or chlorotic mottling distributed in patches over the leaf lamina.
• The leaves are narrower and smaller than normal and the infected plants are dwarf and lag behind in growth. Such plants do not produce bunches but as a virus reservoir.
• The primary transmission is through use of infected daughter suckers from diseased palnts and the secondary spread of the disease is through melon aphid, Aphis gossypii  and Aphids maidis.

MANAGEMENT:

• The banana gardens should be kept free from weeds.
• Infected suckers should not be used for planting.
• Weeds in the nearby areas should be removed as the virus survives in them in off-season.
• Growing pumpkin, cucumber and other cucurbits between the rows of banana crop should be avoided.
• Early detection by regular inspection of planting and eradication of diseased plants from the field as soon as they are noticed.
• Control of insect vector by spraying Phosphomidon at 1 ml per litre or methyl demeton at 2 ml per litre.
• For effective control of aphids we can use bio pesticides like Dr.Eliminator 250ml/acre.

7.Panama Wilt:Fusarium oxysporum f.sp cubense

Symptom:

• Externally, the first obvious signs of disease in most varieties are wilting and a light yellow colouring of the lower leaves, most prominent around the margins. They eventually turn a bright yellow colour with dead leaf  margins.
• Splitting of pseudostem base is a characteristic symptom.
• When a cross-section is cut, the discolouration appears in a circular pattern around the centre of the rhizome where the infection concentrates due to the arrangement of the vessels. As symptoms progress into the pseudo-stem, continuous lines of discolouration are evident when the plant is cut longitudinally.
• The disease is soil borne and the fungus enters the roots through the fine laterals.
• The pathogen is easily spread by infected rhizomes or suckers, farm implements or vehicles, irrigation water.

MANAGEMENT:

• Proper care should be given when planting susceptible cultivators such Rasthali, Monthan, Karpuravalli, Kadali, Pachanadan by selecting healthy suckers from disease fields.
• Remove and destroy infested plant material after harvest.
• Application Bacillus subtilis @ 2.5kg/ha bactericide can also be applied along with farmyard manure and neem cake.
• About 60 mg of Bacillus subtilis (in a capsule) can be applied in a 10 cm deep hole made in the corm.
• Paring (pralinge removal of roots and outer skin of corm) and dipping of the suckers in clay slurry and sprinkled with Carbofuran granules at 40g/corm.
• Soil drenching of Carbendazim 0.1 per cent solution around the pseudostem at bimonthly intervals starting from five months after planting.