Onion-Small Onion(Aggregatum)(Allium cepa var aggregatum); Alliaceae

CO 1, CO 2, CO 3, CO 4 and MDU 1, CO (On) 5 is a free flowering and seed setting type.

Red loam to black soils with good drainage facilities are ideal. The germination and bulb maturation are affected in clayey soil. It grows well in pH range of 6- 7 and a mild season without extremes of heat and cold.
Plant the medium sized bulbs during April – May and October – November. It requires sufficient soil moisture during its growing period but heavy rains during bulb sprouting and bulb formation affects the crop growth.
Seed bulbs 1000 kg/ha. Medium sized bulbs are to be chosen for planting. Seeds @ 2.5 kg/ha
This is the most common method practised for irrigated crop as it results in high yield and large size bulbs. In plains, seeds are sown during October-November for a rabi crop. In hills, seeds are sown from March to June. Seeds are first sown in well prepared nursery beds of 90-120 cm width, 7.5-10.0 cm height and convenient length. Ratio between nursery area and main field is about 1:20. Seedlings of 15 cm height and 0.8 cm neck diameter are ideal for transplanting and this is achieved in 8 weeks. However, it varies from 6-10 weeks depending on soil, climate and receipt of rain. There is a practice of topping seedlings at the time of transplanting if seedlings are over-grown.
Plough the land four times to a fine tilth. Form ridges and furrows at 45 cm spacing. Plant the bulbs or seedlings on both the sides of the ridges at 10 cm apart.

Irrigate at the time of planting of seedlings and third day and later at weekly intervals. Withhold irrigation 10 days before harvest.

Apply FYM 25 t/ha, Azospirillum 2 kg and Phosphobacteria 2 kg/ha, N 30 kg, P 60 kg and K 30 kg/ha as basal and 30 kg N/ha on 30th day of sowing.
 Apply 25 kg ZnSO4, 2.50 kg CuSO4, 30kg S, and 25 kg MnSO4 /ha as soil application, if the soil is deficient in respective micronutrients.
 Foliar spraying of 0.5% ZnSO4, 1% MnSO4 thrice on 30, 40 & 50 days after sowing.

Apply a dose of 75% of the total recommended dose of superphosphate i.e. 285 kg/ha as basal dose. Azospirillum and Phosphobacteria each @ 2 Kg/ha along with FYM 50 Kg and Neem cake @ 100 kg are applied before last ploughing. Raised beds of 120 cm are formed at an interval of 30 cm and the laterals are placed at the centre of each bed.
Bulbs or seedlings are planted in rows of 20 cm spacing and 12 cm between plants. Planting is done at 6 rows in each bed, thereby it accommodates 55,560 plants in one hectare. Irrigation is done after transplanting or planting the bulbs. Complete wetting is necessary to maintain uniform moisture level.

 Clean cultivation, regular hoeing
 Flooding of infested field will check the thrips population
 Spray any one of the following insecticides: Dimethoate 30 EC @ 1.3 ml/lit. / Fipronil 80 WG @1.5 g/10 lit. /Methyl demeton 25 EC 2 ml/lit.
Onion fly
 Adopt proper crop rotation
Root grub
 Drench the soil with chlorpyriphos 20 EC @ 5 lit/ha

Leaf spot / purple blotch
 Spray mancozeb @ 2 g/l or copper oxychloride @ 2.5 g/l or tebuconazole 25.9% m/m EC @ 1 g/l or metiram 55 % a.i. + pyraclostrobin 5 % a.i. @ 2 g/ l. Add Teepol@ 0.5 ml/l of spray fluid
CIB recommendation
 Spray tebuconazole 25.9% m/m EC @ 1 g/l or metiram 55 % a.i. + pyraclostrobin 5% a.i. @ 2 g/ l
Basal rot
 Seed or bulb treatment with Trichoderma asperellum @ 4 g/kg and basal application of T. asperellum @2.5 kg/ha along with VAM @ 12.5 kg/ha

 Growing two rows of maize as barrier crops around field border
 Selection of healthy onion seed bulbs
 Bulb treatment with Pseudomonas fluorescens @ 5 g/kg + Trichoderma asperellum @ 5 g/kg
 Soil application of P. fluorescens @ 1.25 kg/ha + T. asperellum @ 1.25 kg/ha + VAM Fungi @ 12.5 kg/ha + Azophos @ 4kg/ha + neem cake @ 250 kg/ha
 Installation of yellow sticky traps at 12 numbers / ha for thrips and leaf miner trapping
 Installation of pheromone traps at 12 numbers /ha for cut worm (S. litura)
 Spray application of P.fluorescens @ 5 g/l + Beauveria bassiana @10 g/l on 30 days after planting
 Spray application of azadairachtin 1% @ 2 ml/l on 40 days after planting
 Need based application of dimethoate @ 2 ml/l for thrips / leaf miner / cut worm management
 Need based application of tebuconazole @ 1.5 ml/l or mancozeb @ 2 g/l or zineb @ 2g/l for purple blotch disease management.

Spray Cycocel @ 200 ppm + carbendazim @ 1000 ppm 30 days before harvest to extend the shelf life of onion. Harvesting is done by pulling out plants when tops are drooping but still green. During hot days when soil is hard, bulbs are pulled out with a handhoe. Yield is 12-16 t/ha in 70 to 90 days. 18 t/ha in 90 days for CO (On) 5 onion. Clean and dry the bulbs for 4 days in shade soon after harvest.

Crop Growing districts                                          Perambalur, Trichy, Dindigul, Namakkal, Coimbatore, Erode, Tirunelveli
Major markets in Tamil Nadu                            Dindigul, Palani, Palladam, Madurai, Trichy, Ottanchathiram, Coimbatore and Chennai
Preferred Varieties                                              Co (On) 5
Grade Specification                                                Shape, Size, skin colour, moisture content