Facts you should know about Onion plants

                                      Facts you should know about Onion plants

                                                           History of an Onion plant

Onion plant (Allium cepa) belongs to the family of Liliaceae. It is one of the most important commercial vegetables. It is a native southwest Asia and Mediterranean region, an Important bulb crop since the earliest times. It was cultivated in Egypt at least 4800 years ago employed in religious and funerary offerings and has been found in mummies. China, India, Japan, Russia, Turkey, Egypt, Italy, Netherlands, Poland, and Pakistan are the chief producer of the Onion plant.

                                                        Descriptionof an Onion plant

An onion plant is the biennial plant mainly grown as an annual crop. The hollow linear cylindrical leaves have a sheeting leaf base. The food is stored in the bulb during the first growing season. The bulb consists of the short disc-like stem surround by a number of centric layers of fleshy leaf bases, at the end of the first growing season, a leafless scope is produced by a terminal bud that bears in an umbellate inflorescence. The flowers are small greenish and fruit is a globular capsule.

                                                            Uses of an Onion plant

On average, a mature Onion plant contains 87% moisture,11% carbohydrates, 1.2% protein, 0.4% minerals, .1 % fibers, and traces thiamine, nicotinic acid, riboflavin, and vitamin C. the pungency of Onion plant are due to the volatile oil, allyl propyl disulfide. It is a popular vegetable and eaten raw or cooked in various ways and also used for flavoring and pickling. It stimulates diuretic and expectorant and is used against flatulence and dysentery.

                                                             Cultivationof Onion plant

Allium cepa Is a cool-season plant.it grows well under mild climate without extreme heat or cold or excessive rainfall. The ideal temperature required for the crop is 12.5 ⁰C to 21 ⁰C before bulbing and 15.5 ⁰C to 25 ⁰C for bulb development. It can be grown on all types of soil, however, deep friable loam and alluvial soil are the best for its successful production. Free drainage, freedom from weeds, and the presence of organic matter favor the production of good crops. It cannot grow in alkaline or low lying marshy lands. The optimum pH is 5.8 to 6.5.

 Land preparation for Onion plant:

Medium land should be ploughed for Onion plant after the harvest of paddy for 4 to 5 times till a fine tilth is obtained. Remove the root stubbles and incorporate FYM/compost at the time of final land preparation

Seed rate:

 For better production of the crop 10kg/ha of seed is required

Raising of seedling:

Raise seedling in 3m × 1.5m nursery bed and incorporate 20kg of well-composed FYM/bed. Nursery of 0.05 ha with 10 kg of seed will be sufficient for raising seedling for transplanting one ha of land. The first week of October is considered as the best time for sowing the seeds in nursery.

Transplanting:

Prepare 30m ×3m sized beds and transplant 45 to 60 days old seedling of 15 to 20 cm height at a distance of 15 cm row to 10 cm plant to plant. Planting should be complete in the first fortnight of December.  

Manuring:

Apply 25 to 30 t of FYM/compost, 120 kg of nitrogen,60 kg of P₂O₅, and 100 kg of K₂O/ha. 50% of nitrogen full dose of phosphorous and 50% of K₂O should be applied to the basal. The remaining quantity nitrogen should be given into two splits i.e. at the third and sixth weeks after transplanting. Rest 50 of K₂O should be given at second top dressing along with the second split of nitrogen.

Intercultural:

Three weeding and light hoeing are required for the crop. In early-stage irrigate the crop at a short interval and increase the frequency of irrigation with an increase in age of crop and decrease with maturity. Moisture stress decreases the yield.

                                                                Harvesting of an Onion plant

The onion plant is matured in the fourth month. Harvesting should be done when 50% tops fall. Onion are made into bundles and dumped in the field for curing

                                     Onion plant diseases and its management 

                                                    Black Mold (Aspergillus Niger)

Don’t forget to wash your hands when you can contact-with fungus. Fungal spores are widely distributed on the onion plant.

Management:

Treat seeds with appropriate fungicide prior to planting to reduce rot in mature bulbs, avoid bruising bulbs during and after harvest, storing at a temperature between 15 ⁰C (59F), prevents mold spreading but it will remain resume once the temperature increases.

                                              Botrytis leaf blight (Botrytis Squamosa)

High humidity and warm temperature favor the disease in onion plants

Management:

Plant the onion in single rows allowing at least 30cm between plants to promote good air circulation and quick drying of foliage after rain. Time irrigation to allow plants. Time to dry out sufficiently apply appropriate fungicide sprays when plants have at least five true leaves and early symptom of the disease.

                                               Downy mildew (Peronospora Destructor)

Disease emergence favored by the cool temperature and leaf wetness

Management:

Avoid planting infected seeds rotate crop to non-allium species for 3 to 4 years. Plant in well-draining areas and don’t overcrowded plants destroy all infected crop debris, apply appropriate foliar fungicides taking care to apply thoroughly to many ways

                                                 Fusarium basal plate rot( Furasium Oxysoprum)

Moderate to high temperature enhance the disease severity

Management:

Rotated with non-susceptible crops for at least four-year plant resistance onion plant varieties

                                                 Furasium damping off (Furasium Oxysporum)

 Moist to wet soil increase the decreased severity. Plant only decreases free seed, treat seed with fungicide, rotate crop with cereals or grasses to reduce the level of pathogens in soil, steam treatment or fumigation of soil can help the reduce level of Furasium in soil.

                                                    Pink Root (Phoma Terrestris)

Disease is not severe when onion plants are planted continuously or in one year, rotation of 3 to 5 years is preferred. Plant more resistance verities. Solarization and fumigation can help reduce the level of pathogens in the soil.

                                                      Purple Blotch (Alternaria Porri)

Cultural controls include long rotation with non-hosts and reduction of leaf wetness by planting in well-draining soil and time irrigation to allow plants to dry adequately during the day. Some fungicides are effective at controlling the disease.

                                                      Rust (Puccinia Porri)

Favors high humidity but low rainfall. No resistance knows, use only disease-free seeds and plant in well-draining soil control weeds around the crop, apply appropriate protective fungicides.

                                                      Smut (Urocytis Colchici)

No resistance to the disease known in onion plants during the period when promoting rapid growth. Plant only healthy sets, they will not become infected.   

                                                    Leaf steak and bulb rot (Pseudomonas Viridiflava)

Avoid fertilizing plants during winter, apply the appropriate bactericidal spray.

                                                    Pythium seed rot damping-off (Pythium Irregulare)

Control of disease is independent of minimizing soil moisture breakup completed soil. Plant in a well-draining area or raised beds treat seeds with appropriate fungicides prior to planting.