SMS (Plant protection)
Krishi Vigyan Kendra, Tuensang
The plant banana, Musa paradisiacal is the world’s largest herbaceous plant and belongs to the family Musaceae and is one of the most widely consumed fruits in the world. Curved yellow fruit packs a big nutritional punch, wrapped in its own convenient packaging. Today bananas are grown in at least 107 countries and are ranked fourth among the world’s food crops in monetary value. Banana is an instant energy booster, and is one fruit which is commonly available across the globe. A look into the nutritional breakdown of bananas and it reveals the following : per 100 grams, it contains 0.30 gm total fat, zero cholesterol, 1 mg salt, about 360 mg potassium, 2.6 gm dietary fiber, 12 gm sugar and 1.1 gm protein. However banana is attack by many pests and diseases.
IMPORTANT INSECT PESTS
1.BANANA PSEUDOSTEM BORER (Odoiporus longicollis)
Banana pseudostem borer is the most damaging insect and cause more than 30 percent loss yield. Cultivars such as Giant Cavendish and Dwarf Cavendish are more susceptible than Poovan.
Damage symptoms: Both the grubs and adults cause the damage. Leaves turn yellow and the plants are susceptible to wind damage because of tunnels made by O. longicollis. Presence of holes and jelly exudation from pseudostem indicates the presence of larvae inside the stem. White coloured larvae are responsible for riddling of pseudostem and causing serious damage. If the larval tunnel passes through the central growing point, the plant is killed. Larva’s characteristic habit of cutting a rectangular hole just before completion of the cocoon helps in locating the cocoon inside the pseudostem. In the advance stage of infestation, the severely affected plant breaks or topples down along with the bunch.
Management: The most practical method of combating O.longicollis consists of prevention by means of clean culture, accompanied by trapping the adults. Clean culture should include the removal of trash which provides hiding places and removal of broken and decaying plants which serve as breeding places. Practice of cutting off the stems at a height of 2 to 6 feet and allowing these to remain until they disintegrate provides ideal breeding conditions for the beetle. After crop harvest, pseudostem should be removed and burnt. Manual collection and killing of adults. Prune the side suckers every month. Use healthy and pest free suckers to check the pest incidence. Do not dump infested materials into manure pit Uproot infested trees, chop into pieces and burn.
2.BANANA RHIZOME WEEVIL
Banana rhizome weevil is also a damaging insect pest and directly affects the yield. Cultivars such as Giant Cavendish and Dwarf Cavendish are more susceptible than Poovan.
Damage symptoms: Both adult and grub feed at night on the corm, underground parts and pseudostem. Weevil lays eggs into lower portion of pseudostem. Eggs develop into white larvae that riddle the rhizome by making tunnels. Grub of weevil bores into the rhizome and cause damage. Larvae and weevil damage the central portion of pseudostem and reduce plant vigor and cause dead heart.
Management: Selection of healthy suckers for plantations. Do not take regular crop in the same field to avoid initial infestation. Destruction of infested rhizomes, chopping the infested pseudostem into small pieces and scatter them in the plantation. Trimming the infested rhizome. Treatment of rhizome with neem extract @ 0.4% for 1 hour. Clean cultivation.
Aphid is a serious problem in bananas but not for feeding habits but it acts as a vector of banana bunchy top disease, the most damaging virus disease of this crop.
Damage symptoms: Nymphs and adults congregate under the outer sheath base of pseudostem and around the crown and suck the sap. This can cause plants to become deformed; leaves become curled and shriveled, and in some cases galls are formed on the leaves and undersized fruits. Aphids excrete honey dew. This honeydew serves as a medium on which sooty mold grows. Sooty mold blackens the leaf, decreases vigor of the host. They are persistent vector of bunchy top virus.
Management: Rogue out the virus affected plants before spray. Conserve natural enemies. They are important in natural control of aphids. Regular monitoring of the crop. Control weeds around bananas. Apply neem oil/garlic extract/tobacco leaf extract @5ml/litre of water. Spray 200 ml of dimethoate in 250 litre of water at 15-20 days interval after pest incidence.
Damage symptoms: They are most abundant during rainy season (June-Sept). Adults feed on tender leaves of central whorl and skin of young fruits. Fruits become blemish, flavor and market value is lost.
Management: Removal of weeds from basin and unwanted suckers. Keep the plantation free of weeds. In severe infestation apply quinalphos 25EC @2ml/litre of water.
(Musa virus 1)
Banana bunchy top disease is a serious disease of banana. Once established, it is extremely difficult to eradicate or manage. The causal organism is banana bunchy top virus. Cavendish group is highly susceptible.
Damage symptoms: Leaves of an infected plant become bunched together at the apex of the pseudostem. Leaves become dry and brittle and stand more erect than normal giving the plant a rosette ‘bunchy top’ appearance. Margins of the leaves become waxy and in the later stage roll upward. Petiole is reduced in size. Whole plant gets stunted. Leaves show dark green streaks. Infected plants rarely produce a fruit bunch after infection and do not fruit in subsequent years.
Management: Eradication of diseased plant. Plants can be killed along with aphids that are feeding on them by pouring kerosene. Planting of virus-and aphid free suckers. Quarantine measure to check the movement of infected planting material from one place to another.
Yellow and black sigatoka are common fungal disease of banana and Cavendish group is highly susceptible.
Damage symptoms:It causes losses
by reducing the functional leaf surface of the plant, which results in small, unevenly ripened bananas that fail to ripen and may fall. Disease first appears as small, light yellow spots parallel to the side veins of leaves. A few days later, the spots enlarge in size and turn brown with light gray centers. Such spots soon enlarge further, the tissue around them turns yellow and dies, and adjacent spots coalesce to form large, dead areas on the leaf. Rapid drying and defoliation of mature leaves are the characteristic features of this disease.
Management: Remove and destroy diseased leaves, as this will reduce source of infection. If diseased leaves cannot be removed from the plot and burnt, they should be deeply buried. Overhead irrigation encourages the disease. Under canopy micro-irrigation or drip irrigation is preferable. Avoid overcrowding of plants. Application of bordeaux mixture 0.1 per cent + 2% linseed oil can manage the yellow sigatoka disease. Systemic fungicide propiconazole (tilt 25%EC) and carbendazim (bavistin 50 wettable powder) firstname.lastname@example.org% is effective.
(Fusarium oxysporum f.sp cubense)
Damage symptoms: This is the soil-borne fungus that attacks the roots and blocks the vascular system in the banana, so that the plant wilts. Fusarium wilt appears as yellowing of the bottom leaves first. Yellowing begins along the margins and spread rapidly towards the midrib. Leaves finally break at petioles, dry up and collapse leaving a ‘skirt’ of dead leaves draped around the plant. Infected leaves fall in order from oldest to youngest. Leaf sheaths at the base of the pseudostem develop longitudinal splits. When the pseudostem is cut at the bottom, the vascular bundles appear reddish or purple. This is the most characteristic symptom.
Management: Planting of healthy suckers obtained from diseased free areas. Removal and destruction of infected plants. After removal of affected plants, the pits should be treated with lime @1-2kg/pit. Growing of paddy followed by banana for 3-5 years once or twice. Highly infected soil should not be replanted with banana at least for 3-4 years. Treatment of the suckers by dipping in 0.2% carbendazim (bavistin 50 wettable powder) for 45 minutes. When the disease is noticed in early stage in the field, chemical control will be effective. A 10 cm hole is made in the diseased corm at an angle of 45 degree. The hole is filled with 3 ml of 0.2% carbendazim solution during 5th, 7th and 9th month of planting. In areas where fusarium wilt is endemic resistant varieties such as ‘Cavendish’, ‘kisigame’, Mararu’, and ‘Uganda green’ should be grown. Application of bioagents, such as, Trichoderma viride or Pseudomonas fluorescence in the soil is effective.
Conclusion: Banana crop is affected by a number of pests and diseases and have a serious impact on the economic output of a farm. Farmers should be encourage to take up various prevention and treatment methods depending on the crops they grow and the pests or diseases they are susceptible to, as they affect crops differently. Farmers also need to ensure that they balance pests and disease prevention and treatment methods against damage to the environment and also know how to control pests and diseases in different types of combinable crops as an essential task, how to spot early signs of certain diseases, the symptoms that they show, how the disease or insect pests is caused and spread, and how to prevent certain pests or diseases completely and reduce the effect of others.
Banana crop is infested by a number of sucking and chewing pests. Beetle, weevil and borer pose a major problem as a result pest management becomes difficult as more and more pests are added to the ecosystem. Pest suppression can be achieved through judicious use of pesticides, certifying seed, crop rotations, destruction of crop residues, introduce natural enemies and other cultural practices. A key to pest management is to understand pest life cycles and ecology and then to integrate feasible options. Therefore greater understanding of the entire agro-ecosystem and total crop management and active participatory approaches will prove effective for pest management in the present scenario.
The crop banana is also infected by viral and fungal diseases. Diseases can be controlled with frequent applications of fungicides, certifying seed, and cultural practices, such as practise of good hygiene, avoid large areas of any one variety of crop, especially in high disease areas, regular monitor of crops for diseases and resistance, and adequate spacing of plants and efficient drainage within plantation.