Cluster onion (Red onion)


Red onion (Allium cepa L.) is important as a condiment, vegetable and a medicine in Sri Lanka. It is a main producing alliaceous crop in addition to the big onion. National requirement of the red onion is about 100,000 Mt/ year. But, annual production is around 60,000 Mt. Rest of the requirement is imported.

Extent and Production (2007-2015)

Year

Season

Extent (ha)

Production (Mt)

 

Total

 

Total

2007

2006/07 maha

2730

5610

27880

57040

 

2007 yala

2880

29160

 

2008

2007/08 maha

2490

4880

24530

49290

 

2008 yala

2390

24760

 

2009

2008/09 maha

2180

4500

21040

46230

 

2009 yala

2320

25190

 

2010

2009/10 maha

2520

5220

31730

61810

 

2010 yala

2700

30080

 

2011

2010/11 maha

2750

6140

33940

72340

 

2011 yala

3390

38400

 

2012

2011/12 maha

2300

6130

46390

73970

 

2012 yala

2350

27580

 

2013

2012/13 maha

2390

4590

31090

55590

 

2013 yala

2200

24500

 

2014

2013/14 maha

2720

4790

40100

63210

 

2014 yala

2070

23110

 

2015

2014/15 maha

2730

4870

35210

61200

 

2015 yala

2140

25990

 

Source: Department of Census and Statistics, Sri Lanka


Major growing Districts

Jaffna                  Killinochchi

Vavuniya             Trincomalee

Puttalam              Monaragala



Agroecological Zones of Sri Lanka


Cropping Seasons in growing Districts for Red and Big Onion











Recommended varieties and cultivars

 Variety/cultivar

 

Thinnavely Red

 

 

•    Recommended in 2009 for Northern area
•    Dark pink colour bulbs
•    Equatorial Diameter 1-2.5 Cm
•    Polar  Diameter 1.1- 1.5Cm
•    High pungent
•    Maturity at 45 - 60  days after planting
•    Average Yield  11 - 17t/ha

 Vethalan

 

 

•    Most popular cultivar
•    Bolting type
•    Pink colour bulbs
•    Equatorial Diameter 1.5 – 2.5Cm
•    Polar Diameter  2 – 2.7Cm
•    High pungent
•    Maturity at 80-  90 days after planting
•     Average yield 15 - 20 t/ha

 Jaffna Local

 

 

•    Popular cultivar in Jaffna & Trincomali districts
•    Dark pink colour bulbs
•    Equatorial Diameter 1 – 1.5Cm
•    Polar Diameter  2 – 3Cm
•    High pungent
•    Maturity at 60- 75 days after planting
•    Average yield 12 – 15t/ha

 Thelulla Selection

 

 

•    Most popular cultivar at Thellulla in  
      Monaragala district
•    Pink colour bulbs
•    Equatorial Diameter  1- 1.4Cm
•    Polar Diameter  2- 2.7Cm
•    Maturity at 60 – 75 days after planting
•    Average yield 10 – 12t/ha

 
Other Popular cultivars in Northern region

•    Gal Vethalan
•    Muri Vethalan
•    Kunduvallari
•    Poovallari

Climatic Requirement
•    Suitable up to 500m elevation. Not recommended over 500m of elevation
•    A spread rainfall is better at the growth stage.
•    1- 1 ½ months of dry period essential at the maturity stage.

Soil
•    Well drained sandy loam and sandy clay loam soil are good.
•    Can be grown in Reddish Brown, Regasole, Alluvial and Red Yellow Latasolic soil.
•    pH should be 6.5 – 7.8

Planting materials and seeds requirements
•    True seeds – 5-6 Kg /ha  (Vethalan)
•    Seeds bulbs – 1500 – 1750Kg/ha (Vethalan, Jaffna Local, Thinnavely Red, Thelulla
      selection )

Nursery Management
•    Mid March to mid May is suitable for seed sawing.
•    Well drained loamy soil with direct sunlight land suitable for nursery preparation.
•    Nursery should be sterilized (burning, solarization,chemical) before seeds sawing.
•    30- 40 g of seeds need for 3m x 1m x 15 Cm of plot.
•    15 Kg of Compost, 5g of Urea, 15 g of TSP and 10 g of MOP should be added to a
      nursery plot before seeds sawing.

 Burning

 Solarization

Chemical Treatment

Seeds Treatments

  • Captan / 1Kg of True seeds
  • Seedlings should be dipped 15 minuets in 2% Homai solution
  • Seed bulbs should be dipped 30 minuets in 2% Homai solution




Field Establishment

Spacing for

  • Bulblets/seedlings – 8 Cm x 8Cm , 10Cm x 10Cm
  • Bulblets for Bolting – 15 Cm x 15Cm

   

Fertilizer Requirement

  • Highly response for N, P, K and S nutrients.
  • 10t/ha of compost should be added before 1 week of planting
  • Chemical fertilizer

For bulb onion

 

Urea (Kg/ha)

TSP (Kg/ha)

MOP (Kg/ha)

Basal (1-2 days before)

65

100

50

3 weeks after planting

65

-

-

6 weeks after planting

65

-

25

 For bolting onion

 

Urea (Kg/ha)

TSP (Kg/ha)

MOP (Kg/ha)

Basal (1-2 days before)

65

100

50

2 weeks after planting

65

-

-

4 weeks after planting

65

-

65

6 weeks after planting

(If need)

65

-

-

 
Water Requirement

  • Moisture should be kept under saturation level.
  • Sprinkler irrigation system is more suitable for the water supply.
  • Water supplement should be stop in 2 weeks before harvesting.


Pests and Disease Management

Weeds Management

  • One day after planting – Alachlor (480g/l) or 2 – 12 days after planting – Oxyfluorfen should be applied to the wet soil. This is enough up to 3 - 4 weeks of weeds management.
  • After that hand weeding should be done. Especially, weeding should be done before the fertilizer application.
  • Some areas (Trincomalee) are threaten with the Cuscuta chinensis . Supervision is important before attack to the crop. Otherwise, hand weeding should be practiced to control the weeds.

 











Insects Management

Leaf eating caterpillar

- Two type of caterpillars are damaged.

  1. Spodoptera exigua
  2. Spodoptera litura

- Green parts of the leaves are eaten and enter to the inside of leaves and damaged it.

  • Management

- Continuous inspection and destroying egg mass.

- Hand picking and destroying larva.

- Application of recommended insecticides.

   Emamectin Benzoate 5% SG

   Chlorfluazuron 50g/l EC

    Metaflumizone 240g/ l EC

    Lamda cyhalothrin

    Diazinon 500g/l EW

Thrips (Thrips tabacai Lindeman)

- Leaves become to yellowing

- Curl the leaves at the severe stage

- Nymphs and adults can be seen on the base of the leaves

  • Management

- Growing of barrier crops like maize around the field

- Application of sticky traps

- Application of recommended insecticides.

Fipronil 50g/l SC

Imidacloprid 200g/l SL

Thiacloprid 240g/l SC

Root eating Ants (Dorylus orientalis)

  • Damage to roots and underground parts of the onion plants
  • Under dry weather conditions, red ants do considerable damages to onion roots
  • Management
          - Exposing of soil to sunlight at the field preparation
          - Destroying crop debris
          - Application of chemicals Diazinon 50 EC

 Bulb Mites (Rhizoglyphus spp.)

  • Attacks to roots and basal plate of onion plants
  • Plants become to yellowing
  • Stunted growth
  • Reduce plant stand
  • Promote bulb rot during storage
  • Difficult to observe through naked eye
  • Damaged can be seen in growth stage and under storage condition

Management:

- Quality planting materials should be used

- Soaking bulbs in miticides before the planting

- Crop rotation

- Fallowing of field

- Regular field inspection

- Flood irrigation

-  Chemical control Hexithiosox


Disease Management

  1. Fungal Disease

Purple Blotch (Alternaria porri)

  • Small spots appeared earlier and gradually they become to large with purple colour appearance.
  • Leaves, flowers and scapes are infected by this
  • High Relative Humidity, rainy and dark environment favor to disease. Under these conditions, disease spread rapidly.

 

Management

  • Healthy planting materials should be used.
  • Seeds treatments should be done before planting.
  • Crop rotation.
  • Seasonal establishment.
  • Select well drain land for cultivation.
  • Remove the infected plant parts from the field and burn them.
  • Chemical control
    Phiraclostrobin 250g/l EC
    Flusinam 50SC
    Phiraclostrobin + Metram 60WG
    Tebuconasole 250g/l EW

Antracnose / Twister (Colletotrichum gleosporidus , Fusarium oxysporum)

  • Curl the leaves at the growth stage of plant and leaves become to light green colour.
  • Oval shape patches can be seen on the leaves
  • Leaves become to dry
  • At the severe stage decay the bulbs
  • Rainy moist environment favor to the disease

Management

  • Healthy planting materials should be used.
  • Seeds treatments should be done before planting.
  • Crop rotation.
  • Seasonal establishment.
  • Select well drain land for cultivation.
  • Remove the infected plant parts from the field and burn them.
  • Chemical control
    Phiraclostrobin 250g/l EC
    Flusinam 50SC
    Phiraclostrobin + Metram 60WG
    Tebuconasole 250g/l EW

 Downey mildew (Pheronospora destructor)

  • Cool (<220C) moist climate with >95% Relative Humidity is favor to disease.
  • Ash colour fungal with black colour dots can be seen on the leaves.
  • Gradually dry the leaves and leaves get yellow colour.













Management  

  • Healthy planting materials should be used.
  • Seeds treatments should be done before planting.
  • Crop rotation.
  • Seasonal establishment.
  • Select well drain land for cultivation.
  • Remove the infected plant parts from the field and burn them.
  • Chemical control
    Phiraclostrobin 250g/l EC
    Flusinam 50SC
    Phiraclostrobin + Metram 60WG
    Tebuconasole 250g/l EW

Fungal bulb rots (Fusarium spp., Sclerotium spp.)

  • Leaves are yellowing from tip to bottom.
  • Bulbs and roots become to decay
  • Some time white colour mycelia and spores can be seen on the base of the bulbs.











Management

  • Plots should be sterilized before the planting
  • Seeds bulbs and seedlings are treated with fungicides
  • Infected plants with soil are removed from the field and soil drenching (Thiofanate Methile 70% WP,Thiram 80%WP, Thiofanate Methile 50%+ Thiram 30% WP) should be done on that place and surrounding area.
  • Water supply should be cut through the infected area.
  • Improve the drainage.

Bacterial Bulb rots (Erwinia spp., Ralstonis spp.)

  • Widely distributed in major growing areas
  • Heavy yield losses are experienced with this incidence

Nematodes

  • Recorded from Jaffna area.
  • Leaves become to yellowing and dry. Stunted growth can be seen.
  • Nodules can be seen on roots.

Management

  • Turn up and expose soil to sun light
  • Application of poultry manure 2 weeks before planting
  • Crop rotation should be done
  • Dip with water
  • Repellent plants (Lemmon grass, Marry gold) can be grown

Harvesting and Storage

  • Harvesting for dry bulbs
    - Application of chemicals should be stopped 3 weeks before harvesting and supplying of water should be stopped 2 weeks before harvesting.
    - After 50% of leaf folding of the plants, press the rest of the plants by using a wooden plate. 2 weeks after that, plants should be harvested.
    - 75 – 90 days after planting can be harvested. It depends on the variety.
    - 2- 3 days should be cure under shade condition. Should not be exposed to direct sunlight.
    - Clean the bulbs by removing dry leaves. Cut the leaves with remaining 1’’ of neck area.
    - Stored in wooden/mesh cages with well ventilation.
    - Onion can be stored as hanging the bunches.
    - Regular inspection is essential. Decaying and sprouting bulbs are removed at the  time of inspection.




    • Harvesting and storage of true seeds
      - When 20% seeds of the umbel are appeared, harvesting should be done.
      - 2- 3 days allow to sun drying and hand crushing is done to remove the seeds from umbels.
      - Winnowing is done to remove debris. Debris can be removed by using water. If seeds are dip in water, drying should be done quickly.
      - Seeds are stored under 8% of moisture content
      - Seeds can be kept around 1 year under the 100C conditions.

    • Harvesting for leafy vegetable
      - Bushy type cluster onions are suitable for leafy vegetable.
      - 50- 60 days after planting ready for harvesting.
      - Selection should be done based on the 0.6- 1.2 Cm of bulb diameter and 30- 60 Cm of leaf length.
      - Should not bruise the green parts.
      - Transport should be done through caters up to market.

     










    • Harvesting for onion bolts
      - Unopened green bolts are used as a vegetable
      - There is a demand from local and export market
      - Harvesting at morning and proper age is important
      - Should be stored in caters

     

    Source:

    Department of Census and Statistics. Sri Lanka.

    Onion seed production and crop husbandry (2015). Field Crops Research & Development Institute. Department of Agriculture.

    Onion leaflets. Regional Agricultural Research & Development Centre. Aralaganwila.

    Socio economic and Planning Centre. Department Of Agriculture

    Pdf.usaid.gov/pdf_docs/pnadt118.pdf

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