Introduction
In India, onion crop is under cultivation for the last 5000 years mainly in tropical conditions. India ranks first in the area and second in production after China, but the productivity is much lower as compared to the leading producers namely China, USA, The Netherlands, etc. The productivity can be increased by growing high yielding varieties and adopting modern agro-techniques.
Soil require for growing Onion
It can be cultivated in a wide range of soils from sandy loam to clay loam with good drainage facilities. The optimum pH would be 6.5-7.5.
Climate
It is adapted to a temperature range of 13-24° C for vegetative stage and 16-21° C for the bulbing stage, 30 -35° C at maturity and harvest. It performs best in a mild weather without the extremes of cold, heat and excess rainfall.
Season |
Kharif Season | May-September |
| Late Kharif Season | August – February | |
| Rabi Season | October – April |
Nursery raising for Onion
Seeds are sown on raised beds of 1.2 m width and 3-4 m length. The seedlings will be ready for transplanting in 45-50 days after sowing.
Preparation of the primary field
Plough the land to get fine tilth and incorporate FYM 20 t/ha or 10 tons FYM and 5 tons poultry manure or vermicompost at the time of the last ploughing. Prepare flatbed or broad-based furrow (BBF) for planting.
Spacing: 15X10 cm.
Fertilizers for Onion |
For kharif season Onion | 100:50:50:50 kg NPKS/ha |
| Late kharif Onion | 150:50:50:50 kg NPKS/ha | |
| Rabi season Onion | 150:50:80:50 kg NPKS/ha |
Apply 50% N and 100% P, K & S as basal dose and remaining 50% of N to be applied in two splits at 30 & 45 days after transplanting. Perform dressing before bulb development.
Irrigation of Onion
Irrigation is necessary at the time of transplanting/dibbling of cloves, and light watering should be done on the third day after planting, and subsequent irrigation will be done at 7-10 days interval depending upon the soil condition and season.
Micro Irrigation & Fertigation
By using drip and sprinklers, irrigation should be done once in three days. The operating pressure for the drip system is 1.5kg/cm2 and for the rotary micro sprinkler is 2.5kg/cm2. Through drip, do fertigation by using nitrogen fertilizers (Urea). Apply 50% N as basal dose and remaining 50% of N in seven splits (10 days interval up to 70 days after transplanting) through the drip.
Weed management in Onion farming
Keep the crop weed free for good bulb yield. For transplanted onion, pre-emergence application of Oxyfluorfen (Goal) @ 0.15-0.25 kg ai/ha or Fluchloralin (Basalin) @1.0kg/ha or Pendimethalin (Stomp) 3.5 l/ha combined with one hand weeding is effective in both Kharif and Rabi seasons.
For onion nursery and direct seeded crop, application of Pendimethalin @3ml/liter just after sowing is found best in controlling weeds without affecting the germination, seedling growth, and final stand.
Cropping sequence
Soybean in Kharif season followed by onion in rabi season is the best crop rotation which improves soil fertility as well as monetary returns.
Harvesting of Onion
Harvesting of Onion is done at 50% neck fall stage.
Onion Yield per acre |
Onion (Kharif) | 15-20t/ha |
| Onion (Late kharif) | 30-35t/ha | |
| Onion (Rabi) | 25-30t/ha |
Pest and disease management for Onion
Pest and disease management is crucial for obtaining higher marketable bulb yield and good quality bulbs. Major pests and diseases of onion, their symptoms, and management practices are given in Table. Also, following points need to be considered for pest and disease management.
- Initiate foliar sprays of pesticide from 30 days after transplanting or as soon as pest/disease appears in the field
- Spray at 10-15 days interval depending upon the intensity of pest/disease
- Always add spreader @ 0.5-1.0% to spray solution
- Avoid repeated application of pesticides belonging to the same class
Important pests and diseases, their symptoms and control measures
Spray fungicides, Mancozeb @ 0.25% / Tricyclazole @ 0.1% / Hexaconazole @ 0.1% /Propiconazole @ 0.1% at 10-15 days intervals from 30 days after transplanting or as soon as disease appearsSpay fungicides, Mancozeb @ 0.25% / Tricyclazole @ 0.1% / Hexaconazole @ 0.1% /Propiconazole @ 0.1% at 10-15 days interval from 30 days after transplanting or as soon as disease appears
Pest/disease |
Pest |
Symptoms |
Control measures |
Insects
|
Thrips
(Thrips tabaci) |
1. Thrips infestation at the early stage (transplanting to 45 days) can be identified by curling and twisting of leaves
2. Typical symptom of onion thrips is the presence of white or silvery patches on the leaves 3. In severe infestation, whole the plant looks blemished and turns white. |
1. Planting of two rows of maize or one outer row of maize and one inner row of wheat as a barrier crop surrounding onion crop (250 sq. m) at least 30 days before transplanting helps block the movement of adult thrips
2. Spray insecticide when thrips population crosses the economic threshold level of 30 thrips/plant 3. Foliar spray of insecticides like Profenofos (0.1%), Carbosulfan (0.2%) or Fipronil (0.1%) depending on the severity of infestation |
| Eriophyid mite | 1. Leaves do not open completely. The whole plant shows curling.
2. Yellow mottling is seen mostly on the edges of the leaves. |
1. Spray Dicofol (0.2%) as soon as the symptoms appear in the field. Repeat the spray after 15 days, if necessary.
2. Foliar spray of sulphur @ 0.05% |
|
Diseases
|
Purple blotch (Alternaria porri) | 1. Initially small, elliptical lesions or spots that often turn purplish-brown which are surrounded by the chlorotic margin.
2. If the spots enlarge, chlorotic margin extend above and below the actual lesion. Lesions usually girdle leaves, causing them to fall over. Lesions may also start at the tips of older leaves. |
Spay fungicides, Mancozeb @ 0.25% / Tricyclazole @ 0.1% / Hexaconazole @ 0.1% /Propiconazole @ 0.1% at 10-15 days intervals from 30 days after transplanting or as soon as disease appears |
| Stemphylium blight(Stemphylium vesicarium) | 1. Small yellow to orange flecks or streaks develop in the middle of the leaf which soon develop into elongated, spindle-shaped to ovate-elongate diffused spots surrounded by the characteristic pinkish margin.
2. The spots progress from the tip to the base of the leaves. The spots coalesce into extended patches, blighting the leaves and gradually the entire foliage. |
Spay fungicides, Mancozeb @ 0.25% / Tricyclazole @ 0.1% / Hexaconazole @ 0.1% /Propiconazole @ 0.1% at 10-15 days interval from 30 days after transplanting or as soon as disease appears | |
| Anthracnose/Twister Disease (Colletotrichum gleosporiodes) | 1. The characteristic symptoms are curling, twisting, chlorosis of the leaves, and abnormal elongation of the neck (false stem).
2. Initially, pale yellow water soaked oval sunken lesions appear on leaf blades. Numerous black colored slightly raised structures are produced in the central portion, which may be arranged in concentric rings. The tender leaves shrivel, droop down and finally wither. |
1. Soil treatment with Benomyl @ 0.2%
2. Foliar Spray of Mancozeb @ 0.25% 3. Planting onion on the raised bed 4. Avoid water logging |
|
| Damping off disease | 1. Seedlings topple over after they emerge from the soil. It usually occurs at or below the ground level, and infected tissues appear soft and water soaked | 1. Planting onion on the raised bed
2. Seed treatment with Thiram or Captan @ 0.3%. 3. Drenching the nursery beds by Captan or Thiram @ 0.2% or Carbendazim @ 0.1% or Copper oxychloride @ 0.3% |
|
Viral diseases |
Irish Yellow Spot Virus (IYSV) | Symptoms first appear as straw-coloured, dry, tan, spindle or diamond-shaped lesions, with or without distinct green centers with yellow or tan borders on leaves. Flower stalks have a more clear system. Infected leaves and stalks lodge during the latter part of the growing season. | 1. Plant high-quality transplants free from thrips and Iris yellow spot virus.
2. Practice three years or longer rotation between onion crops. 3. Eliminate volunteers, culls, and weeds in and around onion fields. 4. Avoid plant stress. 5. Thrips control may provide some reduction in iris yellow spot, but thrips control alone is not sufficient to economically control the disease |
| Onion yellow dwarf virus (OYDV) | Mild chlorotic stripes to bright yellow stripes, mosaic, curling of leaves and stunted growth | 1. Use virus free planting material
2. Use resistant cultivars 3. Aphid control will reduce the incidence of OYDV which is a vector for OYDV 4. Foliar spray of insecticides like Profenofos @ 0.1%, Carbosulfan (0.2%) or Fipronil (0.1%) for controlling Aphids |
Source- ICAR-Directorate of Onion and Garlic Research.
