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Agriculture > Fruit Crops > Banana (Musa spp.)

Crop Management

Diseases

Bunchy top disease

bunchy

The disease is transmitted to the plant by the aphid vector Pentalonia nigronervosa and dwarf bananas are very susceptible to this disease. Primary symptoms of the disease are seen when infected suckers are planted. Such infected suckers put forth narrow leaves, which are chlorotic and exhibit mosaic symptoms. The affected leaves are britttle with their margins rolled upwards. Characteristic symptom of bunchy top virus is the presence of interrupted dark green streaks along the secondary veins of the lamina or the midrib of the petiole. The diseased plants remain stunted and do not produce bunch of any commercial value.

Control

  • Use insecticidal treatments recommended for insect vector control.
  • Eradicate disease affected plants.
  • Use disease free suckers for planting. Karpooravally, Kanchikela, Njalipoovan and Koompillakannan are less susceptible varieties.

Panama wilt (banana wilt) (Fusarium oxysporum f. cubense)

Panama wilt

This is a soil-borne fungal disease and gets entry in the plant body through roots. It is most serious in poorly drained soil. Initial symptoms are yellowing of lower leaves, including leaf blades and petioles. The leaves hang around the pseudostem and wither. In the pseudostem of the diseased plant, yellowish to reddish streaks are noted with intensification of colour towards the rhizome. Wilt is severe in poor soils with continuous cropping of banana. Warm soil temperature, poor drainage, light soils and high soil moisture are congenial for the spread of the disease.

Control
  • Dip suckers of susceptible varieties in 2 g/litre carbendazim solution to prevent spread of the disease.
  • Drench the soil around affected clumps with 2 g/litre carbendazim solution to prevent spread of disease.
  • Remove and destroy affected clumps along with corms.
  • Apply lime @ 1 kg/pit and allow to weather. Varieties such as Palayankodan, Robusta and Nendran are resistant to the disease.

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Sigatoka leaf spot (Mycosphaerella sp.)

blak siagtoka

Yellow sigatoka is one of the serious diseases affecting the banana crop. Initial symptoms appear in the form of light yellowish spots on the leaves. A small number of these enlarge, become oval; the colour also changes to dark brown. Still later, the centre of the spot dies, turning light grey surrounded by a brown ring. In severe cases, numerous spots coalesce, killing large parts of the leaf.

Rainfall, dew and temperature determine the spread of the disease. Conditions favouring mass infection are most common during the rainy season with temperature above 21°C.

Control

  • Cut and burn all severely affected leaves.
  • Spray 1% Bordeaux mixture soon after the appearance of the initial symptoms of the disease. The disease appears with the commencement of southwest monsoon. Five to six sprayings at fortnightly intervals are to be given depending upon the severity of the disease.
  • Power oil (mineral oil) 1 g/litre emulsion is also effective in controlling the disease.
  • Spray carbendazim (0.05%) or give alternate sprays of mancozeb 2 g/litre and carbendazim 1 g/litre soon after the appearance of initial symptoms of the disease. Three to four sprayings at fortnightly intervals are to be given depending on the severity of disease.
  • Spraying of cow’s urine (10%) /sucker treatment with Pseudomonas fluorescens 5% + spraying 2% Pseudomonas fluorescens and vegetable oil (2.5 ml/litre) +baking soda (2.5 g/litre)

Kokkan disease (Banana bract mosaic virus)

Kokkan disease was first reported from Thrissur district in the variety Nendran. Later on, the disease was found to affect other varieties like Palayankodan, Kodappanillakunnan, Monthan, Kanchikela, Poovan (Rasthali), Karpooravally and Chenkadali. Nendran is the highly susceptible variety.

During the young stage of Nendran banana plant (two months old), pinkish streaks can be seen on the pseudostem. All the kokkan affected plants need not show this symptom, but once this symptom is expressed there is no doubt that the particular plant is affected with kokkan disease. Necrotic streaks are another important symptom of the disease. The necrotic streaks are initially brown, which later turn black. It occurs on all aerial parts of the affected plant except on lamina, the length being a few mm to 10 cm. All the kokkan-affected plants will exhibit the necrotic streaks from third month onwards at one stage or other. Some of the affected plants retain the necrotic streaks throughout the growth period. In certain cases it disappears with the senescence of the affected portion.

The affected plant produces only a small bunch. The fingers are small, curved and widely divergent with pale green to ashy green colour as compared to the healthy ones. The abnormal colour and reduction in the size of the bunch depend upon the severity of the disease.

Control

  • Suckers should not be taken from affected plants, which show necrotic streaks or abnormal colour of the pseudostem.
  • When the young plants show the symptom of pinkish streaks, they should be uprooted and destroyed.

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Infectious chlorosis (Cucumber mosaic virus disease)

Cucumber mosaic virus disease

The disease is noticed in varieties such as Nendran, Palayankodan, Karpooravally, Kosthabontha, Peykunnan, Bhimkhel, Mottapoovan, Dakshinsagar, Madhuraga, Rasthali and Musa ornata.

The most characteristic symptoms are the loss of leaf colour in patches; appearance of parallel chlorotic streaks on the younger leaves, giving a striped appearance on the leaves. As the disease progresses, leaves emerge distorted, margins become irregularly wavy, often with blotches of necrotic tissues and the leaf lamina is reduced in width. In severe cases, rotted areas are found throughout the leaf sheath and pseudostem. The affected plants produce only small bunches. This is a virus disease transmitted by aphids.

  • Use disease free suckers for planting.
  • Eradicate disease affected plants.
  • Use insecticides recommended for insect vector control.
  • Avoid growing leguminous and cucurbitaceous vegetables as intercrop in banana in disease prone areas.

Banana streak disease

Banana streak disease is caused by banana streak badna virus and transmitted by pineapple mealy bug (Dysmicoccus brevipes Cockerell) and stripped mealy big (Ferrisia virigata Cockerell). It is predominant on palayamkodan variety, also noticed on other varieties like Nendran, chinali, and mottapoovan. The symptoms appear on different parts of the plant such as leaf lamina, midrib, pseudostem, and on bunches. Linear chlorotic streaks appear on leaf lamina which later turned brown streaks. Such dark brown linear lesion appear on petiole, midrib, pseudostem and bunches. Under severe conditions, necrosis and death of cigar leaf is noticed and such plants fail to flower and lead to total yield loss.

For the control of the disease, eradicate diseased plants, do not select planting materials from infected clumps. Avoid growing colocasia as intercrop and control of mealy bug vectors.

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