The onion (Allium cepa L., also known as the bulb onion or common onion, is a vegetable that is the most widely cultivated species of the genus Allium.
By Rifat batool, Fazeela zarin, Ahmad nawaz
The onion plant has a fan of hollow, bluishgreen leaves and its bulb at the base of the plant begins to swell when a certain day-length is reached. The bulbs are composed of shortened, compressed, underground stems surrounded by fleshy modified scale (leaves) that envelop a central bud at the tip of the stem. In the autumn (or in spring, in the case of overwintering onions), the foliage dies down and the outer layers of the bulb become dry and brittle.
Onion are one of the oldest vegetables in the world it make the curry taste and fragrant. In addition to the minerals and phosphorus, it contains protein and vitamin C. It use to controls cholesterol in the blood and protects the people from blood pressure other deadly diseases such as heart disease. The annual area under onion cultivation in Pakistan is 320,000 acres and production are about six million tons. The average yield of onion is 5 tons per acre. Hyderabad division in Sindh, Lahore and Multan division in Punjab, Qalat division in Baluchistan and Malakand division in Khyber Pakhtunkhwa are important areas of onion.
Onion is a cool season plant its optimum temperature for seed germination ranges from 20-250 C early growth stages before building require 13 to 20 0 C and bulb development needs 16 to 250 C. Cold and humid climate is required during onion growth For which a temperature of 13 to 20 degrees Celsius is considered better. Onions are applied in two ways on the peel and on the smooth surface.By this method we can get high yield of onion for nursery of onion 2-3kg seed needed in one acre field there are 1 lac and 60 thousand plants are require.
There are many types of onion which are famous by their taste .In Pakistan middle and large size onion are very successful.in Baluchistan chaltan and sarayab are famous onion verities in Sindh phulkara in Punjab and desi are famous onion verities.
Damage of onion thrips
Onion which use at large sacle are attack by different insect pest e.g onion fly and thrips.at international level onion is infected by thrips.it turn the onion leaves in to yellow colour and spots occur on leaves Onion thrips are tiny insects that range in color from yellow to black and are only 1/16” in length. They spend the winter as adults in crop remnants, alfalfa, wheat, greenhouses and weeds along the border of crop fields. Adults lay eggs singly in the epidermis, nymphs feed on leaves, and pupation occurs in the soil. There are at least two generations per year in the Northeast. Thrips have rasping mouth parts which they use to tear open plant cells to feed on plant juices. Populations are favored by hot, dry weather. Heavy rain or overhead irrigation can lower populations. In onions feeding occurs in protected, succulent areas where new leaves are emerging, deep between the leaf blades. Adults and nymphs pierce the epidermis and cell wall and remove cell contents. Damage may appear as silver lines, white patches, tip dieback, curling and twisting of leaves, slowed growth, reduced bulb size and yields, or if severe enough can result in plant death
Different types of nets are used in onion which contain a variety of capsules they attract the onion thrips, kill it and reduce their population.
Different types of biological insect ladybird beetle, green lacewing eat onion thrips and by their feeding onion thrips population reduce.
Neem seed powder and basil oil are mix with Dimethoate, Acephate and Fipronol insecticides use on thrips by spraying this solution to control it.