Banana Bunch Care and methods to maximize Bunch size

Banana Bunch Care and some proven procedures 

to maximize the Bunch size:

To attain maximum yield in Banana cultivation, follow the latest cultivation practices give here:

A model of 'DBT' certificate

• Prefer Tissue culture banana plants from 'DBT' (Department of Biotechnology) certified biotech companies.

• Avoid cultivating banana in problematic soils like ‘Acidic’, ‘Alkaline’ and ‘Saline’ soils.

• Ensure irrigation water quality and avoid water with EC of >1.

• Give priority to good water management (To avoid water Stress, go for Drip irrigation system).

• Adhere to a strict Integrated Nutrient Management (INM covers NPK, Macro and Micro-nutrients) schedule as given in the following links: Fertigation schedule for banana and Fertilizer target chart for banana (along with the comments section in both the posts).

• Follow good Integrated Pest Management (IPM) practices.

• Follow good Integrated Disease Management (IDM) practices.

• Strictly follow all the 'Bunch care techniques' explained here to maximize bunch size. Always bear in mind that the price of Banana is NOT directly in proportionate to the quality of produce. In the trading of banana, fruit quality is valued more in fixing the price. So, strive to achieve the best in quality.

    Details of Banana Bunch care & methods to enhance the bunch size:

1. Bell injection -  Injection on inflorescence bud to control sucking insect pests infesting on developing fingers:

Bell Injection is given when the emerging inflorescence (Flower) bud is in upright position. It gives complete protection from pests that damage the developing bunch as the bell emerges.

 

The injection should be given at 1 / 4th place from top of the bud.

To prevent clogging of the needle, first make a hole at the desired point with a small needle and then use the syringe.   

Prepare a solution of Imidacloprid 17.8 EC (Brand: Confidor)    @ 0.2 ml in 1 litre of water and take 2 ml solution in a disposable Insulin syringe. Inject the entire 2 ml in the bud in a 30 degree angle.

(OR)

 

Prepare a solution of 0.1% (One ml in 1 litre of water) of Imidacloprid 17.8 EC (Brand: Confidor) and pump a full single dose of 40 ml of the solution into the flower bud thereby fully drenching the bud using "Banana Bell Injector pump". 

Pictures courtesy: http://treeinjectors.com/ and  
http://www.saspl.com.au/product/banana-bell-injection-poster-2/

2.  Banana Deflowering:

                Banana Deflowering

3.  Placing perforated sheet as cushion between separated hands:

Placing perforated sheets between hands

.

 .

4.  De-navelling (Removal of male floral bud):

It helps in fruit development and increase of bunch weight. 

The male flower bud should be removed one month after emergence of the last hand. 

By this removal of unwanted male flower bud, which is prone to infections, incidence of pest and disease attack on bunch can be minimized. 

In some parts of Tamilnadu, farmers leave them as such up to the time of harvest, resulting in elongation of stem with the male flower bud up to the ground.

5.  Covering the peduncle (Peduncle wrapping) to protect it from sunburn or scorching:

Flag leaf / Boot leaf - Nature's umbrella Gift.

A 'Boot leaf / Flag leaf ' emerges from the plant just before the bunch emergence and its main purpose is to protect the top curved part of the peduncle and upper portion of the bunch from sunburn or scorching. 

If this natural protection gets damaged due to wind or pest attack, the upper exposed part of peduncle will get sun burned (Sun scorched). 

This subsequently leads to rotting of peduncle due to secondary infection of 'Colletotrichum fungus'.  Incidence of sun scorching will be severe if bunch emergence coincides with hot summer months. Since nutrient and water flow from the main stem to bunch gets arrested, immature ripening will occur resulting in very poor bunch development and ultimately breaking of the peduncle along with the bunch.

Remedial measures: 

• To prevent sunburn and the resultant fungal infections, the peduncle exposed to scorching sun should be wrapped with the flag leaf and other banana leaf trashes.
• If the sun scorching happens before initiating any protective measure, apply a thick solution of 2% COC (Fytolan or Blue Copper) on the affected area using a wall painting brush and cover the affected portion using banana trash leaves.     

6.  Effects of covering Banana bunch (Skirting) with polythene Bunch covers / sleeves or Non-woven skirting bags :

Usage of Banana bunch cover

1. Bunches are covered with 6% ventilated Polythene covers / sleeves of size 200cm Length x 150cm width x 175 gauge thick. 
2. Use opaque polythene covers / sleeves if bunch development is during winter and paper bags can also be used to avoid chilling injury at frost conditions. 
3. Use blue color bunch cover / sleeves during summer to avoid sun scorch.
4. Do it within 15 days of last hand opening.
5. The bunch is free from insect bites, fungi, bacteria attacks and physical injuries.
6. Improved bunch appeal. 
7. Maturity of bunch will be advanced by 7 to 10 days.

             Placing inserts and skirting the bunch 
with covers / sleeve

Using blue color bunch covers / sleeves 
during summer to avoid sun scorch.

Using Bunch cover made of paper 
to prevent chilling injury at frost conditions

7.   At the banana bunch development stage the following fertilizers are  normally recommended to enhance the size of fruits / bunch: 

Option 1: Application of 2% (20gm / 1litre) Potassium sulphate (0:0:50) as foliar spray on bunches, two times with 15 days interval.

(OR)

Option 2: Application of 1% (10gm / 1litre) Potassium nitrate (13:0:45) as foliar spray on bunches, two times with 15 days interval.

(OR)

Option 3 (Considered as best since it addresses all nutritional deficiencies): Application of 0.5% (5gm / 1litre) Potassium nitrate (13:0:45) + 0.5% (5gm / 1litre) of foliar grade Micro nutrient mixture as foliar spray on bunches as first spray followed by a second application of 2% (20gm / 1litre) of Potassium sulphate (0:0:50) + Biozyme 2ml / 1litre after 15 days. Repeat the second one again as III application after 15 days interval.

Important Note 1: In all the above applications you can also add 0.2% Bavistin (Fungicide) for prophylactic control of fungal infections. Use wetting agents also. 

Important Note 2: Nowadays farmers are going for a minimum of four applications within a period of 60 days (4 sprays with 15 days interval between each spray) and are getting very good results. 

Precautions: 

• Care should be taken to spray the above fertilizers only after all the hands are fully opened and after sufficient extension of male flower bud in the rachis. 
• Do not apply any fertilizers or pesticides 15 days before harvest since there is a possibility of the unabsorbed chemical residues entering human food chain.
• Application of excess dosage of fertilizers, Enzymatic and synthetic Growth promoters and plant protection chemicals on bunches are to be strictly avoided. See the link:Effect of overdose.

Option 4:    Enhancing banana bunch yield through feeding N and K through distal end of rachis: For detailed procedure click this Link.

There is considerable increase in bunch size in ‘Robusta’ and ‘Grande naine’ banana, when feeding the following mixture through the distal end of rachis soon after fruit set.  

Preparing the nutrient mixture:

• Ammonium Sulphate            -           15gm
• Sulphate of potash (SOP)    -           7.5gm
•  Fresh cow dung                    -           500gm blended in 100 ml of water.

(Cow urine can also be used instead of water. 500 gm of fresh cow dung contains substantial amounts of about 5.5gm of N, 3.5gm of K 1.6 gm of S besides other minerals and bio-chemicals).

Method of application:

v     Select bunches where the fruit set is complete and about 10 – 15 cm long rachis is available after the last hand. Avoid bunches where fruit set is incomplete or during partial deflowering time.

v     Remove male flower bud close to the rachis.

v     Take the already prepared nutrient slurry in a used milk bag.

v     Insert the slurry filled bag into the de-navelled stalk end of the bunch and tie it with a strong string.

Benefits:

Ø      Bunch weight increased by 67% over control in which male flower bud was retained till harvest. In the field demonstrations, a response of 22 % to 28% increase in bunch weight was evident. Using ‘N-isotope label the movement of 51% of N into the bunch from AmSo₄ was confirmed.

(Courtasy: ICAR News, Research update, Success story, April – June 2007).

For EXPORT of banana fruits, buyers normally insist on the following practices also in addition to the ones described above:

8.  Size of fruit preferred for export:

41mm fruit measuring tool kit

•  Exporters won’t prefer fully developed bunches that are ready for harvest. A bunch with a middle fruit in It’s 2nd hand measuring 41 mm dia, and the middle fruit in the last Hand with 35 mm dia two weeks before harvest is ideal for Export.

 

• Normally there will be variation in the size of fruits located in the upper hands and lower hands. Fruits in the upper hands are always bigger than fruits in lower end hands.  The variation will be more and markedly visible if there are more than 10 hands (sometimes 13 to 15 hands) in the bunch. To procure more or less uniform size of fruits, exporters insist the farmers to maintain only 9 or 10 hands in the bunch. By restricting the number of hands to 9 to 10, availability of nutrients to the fruits are more resulting in uniform size of fruits and faster development. 

41mm is preferred fruit size for export

9.  The practice of ‘Finger thinning’ is also to get uniform size of fruits.

10.  Retaining a finger in the last hand: 

After de-navelling (removal of male floral bud), the distal end of rachis sometimes gets infected with fungus and if left uncured the fungal infection spreads to the upper hands causing extensive damage. Retaining a finger in the last hand is a practice to monitor the fungal infection since the symptoms can be easily spotted in a lone fruit rather than spotting it in the major part of the bunch.

Leaving a single finger in the last hand

Excellent yields are obtained in many fields of farmers at Theni District, Tamilnadu, where the farmers followed only few of the bunch care techniques described here above. But, they meticulously followed the 'Bunch sprays' described in Sl.No.6, Option 3, Important Notes 1 & 2  and covered the bunches with bunch covers / sleeves. To attain max. yield in banana, the crop has to be nourished properly from day one. One of the main reason for the farmers achievement other than bunch care and bunch sprays is their adherence to the "Fertilizer Target Chart" (Link: Fertilizer Target Chart for better nutrition management in banana - Kindly refer the comments section also for better understanding) given to them for giving timely, adequate and balanced nutrition to the crop.

     

Regards,

A.Vishnu Sankar.

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Posted in: 24. Banana Bunch care - Methods to maximize bunch size

Insect Pests – Rhizome Weevil / Corm borer

Insect Pests – Rhizome Weevil / Corm borer:

Symptoms:

Adult weevil (Cosmopolites sordidus) is black and mostly found in between leaf sheaths and in the soil at the base of the rhizome. Rhizome weevil interfere with the root initiation, kill existing roots that limits nutrient uptake, reduces plant vigour, delays flowering and increases susceptibility to other pests and diseases.

Larvae of the weevil furrow into the rhizome at different locations creating a network of hollow tunnels which are not visible externally. Larvae sometimes bore into the pseudostem also. 
Infestation at the early stage reduces plant vigour. Sick appearance and yellow lines on the top leaves are early symptoms.

In the advanced stage of infestation, plant shows tapering of stem at crown region, reduction in the leaf size, poor bunch formation and choked throat appearance due to grub damage in the corms. Attacked rhizome and pseudostem gets girdled with holes that result into toppling of the plants. The weevil spreads through infested suckers to different places.

Rhizome weevil / Corm borer affected plant

Rhizome weevil / Corm borer affected corm

Rhizome weevil / Corm borer affected suckers and corm

Usage of Pseudostem injector to control Rhizome weevil / Corm borer

Control:

1. Keep the plantation clean without weeds, remove trashes and burn the refuse. 
2. You can be rest assured of infection free planting material if you go for ‘Tissue culture plants. Avoid planting of borer infested suckers. To make sure that you have clean suckers, the roots should be trimmed and pared-off all tissues on the surface to make it free of any infestations and dip the pared corm in a solution containing 0.5% Monocrotophos or Trizophos 2.5 ml in 1 litre solution for 30 minutes. Alternatively application of 40g of Carbofuran in the soil at planting can also be followed. 
3.  Dilute Monocrotophos 150 ml in  350 ml of water and inject 4 ml in the rhizome using Pseudostem injector in a 45 degree slanting angle. For more details click this link: A novel method for effective control of Weevil attacks in Banana plants. 
4. Rake the soil around the rhizome and apply through drenching 2 gm / litre Carbaryl or 0.03% Chlorpyriphos or 10 g / plant Carbofuran 3G or 10 gram / plant Phorate 10G two times at 10 days interval followed by tight watering.

Regards,
A.Vishnu Sankar

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Posted in: Insect Pests – Rhizome Weevil / Corm borer

Insect Pests – Pseudostem Weevil / Borer

Insect Pests – Pseudostem Weevil / Borer:

Symptoms:

The Pseudostem weevil (Odoiporus longicollis) are normally black coloured ones but red coloured variants are also found in some areas. The pest breeds and become more active during summer and monsoon seasons.

Early symptoms of infestation are the presence of small pin-head sized holes on the pseudostem, fibrous extrusions from bases of the leaf petioles and exudation of a gummy substance from the holes of the pseudostem.

The weevil larvae are fleshy and yellowish white. Larva bores hole through the pseudostem and thrives inside. This results in exudation of plant sap followed by dropping of the faecal matter. As the central core is destroyed due to the boring of the larvae, upward movement of the nutrient is hampered which ultimately results in poor growth and development of the plants.

If the larva tunnels pseudostem during advanced pre-flowering stage, the ascending flower bud and peduncles are destroyed resulting in non emergence of the flower bud which decays inside the pseudostem. This leads to choked throat appearance of bunch and breaking of Pseudostem.

During advanced stages of infestation, we can observe by splitting the stem, the pests' extensive tunneling both in the leaf sheath and in the rhizome. Rotting occurs due to secondary infection of other pathogens and foul odour is emitted. When the rhizome and peduncle are tunnelled after flowering, the fruits do not develop properly, exhibiting a dehydrated condition with premature ripening of the bunch.

Pseudostem weevil affected plant with immature bunch

Pseudostem weevils / grubs

Pseudostem weevil attack - Bore hole on Banana

 Control:  

1. Keep the plantation clean.  
2. Remove trashes and burn the refuse. 
3. Do not dump infected plant into manure pit. 
4. Uproot infected trees, chop into pieces and burn. 
5. You can be rest assured of infection free planting material if you go for ‘Tissue culture plants. If you opt for suckers, then avoid planting of borer infested suckers. To make sure that you have clean suckers, the roots should be trimmed and pared-off all tissues on the surface to make it free of any infestations and dip the pared corm in a solution containing 0.5% Monocrotophos or 2.5 ml in 1 litre solution of Trizophos for 30 minutes. Alternatively application of 40g of Carbofuran in the soil at planting can also be followed. 
6. Do not plant susceptible varieties in the endemic areas such as Nendran, Mondan, Ney poovan etc. 
7. Dilute Monocrotophos 150 ml in  350 ml of water and inject 4 ml in the pseudostem about 2 feet higher from the ground (preferably below bore hole) using Pseudostem injector in a 45 degree slanting angle. For more details click this link: A novel method for effective control of Pseudostem weevil using Pseudostem Injector. 
8. Rake the soil around the pseudostem and apply 0.1% Metasystox or 0.05% Quinalphos or 0.03% Chlorpyriphos or 0.2% Carbaryl followed by light irrigation, at 15 days interval.  
9. Method to trap the weevil with spilt pseudostem: The freshly cut pseudostem is a good breeding place for weevils. So, after the bunch has been harvested, cut the pseudostem close to the ground then cut it into small pieces in lengths of up to 60 cm, split each along its length and place them in the soil in the way that the cut portion faces the ground. These cut pieces (split traps) attract adult female weevils to feed and lay their eggs. As soon as the larvae emerge, these pieces become dry and eventually the larvae die because of dehydration. This split trap method to trap the weevil is just to monitor the extent of infection in the field and control measures have to be taken up immediately.
10. The open cut side of the above pseudostem cut pieces about 30 to 40 numbers (split traps) can be sprayed with 0.5% solution of Beauveria bassiana or  Metarhizium anisopliae,  both are entomopathogenic bio control agents before placing them face down on the soil. The weevil gets infected by the fungal conidia (spores) when it enters the pseudostem trap. It is enough for the conidia of the fungus to come in to contact with the body of the weevil or ingested where it grow and colonize the host body. Then they germinate and the hyphae that emerge penetrate the cuticle of the insect host. After extensive invasion of the host body, the Destruxins produced by the fungus eventually weaken and kill the insects within 72 hours.
11. Use Pheromone traps (2 traps/acre) and destroy the collected weevils. 

A Pseudostem Injector and a Pseudostem cut piece for weevil trap

Regards,
A.Vishnu Sankar

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Posted in: Insect Pests – Pseudostem Weevil / Borer

Fungal Disease (Pre & Post Harvest): Fruit Freckle / Leaf Freckle

Fungal Disease (Pre & Post Harvest):
Fruit Freckle & Leaf Freckle: 

Symptoms:

Causal organism of this disease is a fungus which has two names, Phyllostictina  musarum and Guignardia musae because the fungus produces two types of spores causing brown to black coloured small and large spots on the leaves and fruits.

These spots can run together to form streaks. Severe infection results in yellowing followed by withering and ultimately death of the leaves.

The most characteristic symptom of both types of spots is a sand paper feel of the leaf and fruit surface. The fungus normally grows on the dead hanging leaves and spreads to fingers during rainy and windy weather.

 

Freckle disease on banana leaf

Freckle disease on banana fruit

Control:

• Removal infected and dried leaves at regular intervals. 
•  Spray at weekly interval once or twice or dip the unripe harvested fruits in 0.05% Bavistin or 0.25% Mancozeb. 
•  Using Polythene bunch cover is found to be effective.

Regards,
A.Vishnu Sankar

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Posted in: 50. Fungal Disease - Fruit Freckle / Leaf Freckle