Sunflower; a wise choice among oil seeds
Pakistan produces only ¼ of edible oil of its need, however, remaining ¾ have to be imported. Almost 212 billion rupees are spent annually to import edible oil like sunflower.
It is need of the time that cultivation of oil crops must be promoted among farmer community and to minimize the dependence on import which will ultimately reduce the expense at edible oil importation.
Sunflower has a significant status among oil crops. It is a short duration crop. Its seeds contain 40-48% high-quality edible oil which contains unsaturated fatty acids in large amount. As it contains a low amount of saturated fatty acids, it is good for heart diseases as well as it comprises vitamin A, B and K due to which it is considered as very beneficial regarding human health.
In our country, the sunflower is grown two times in a year but still, its average production is lower than other developed countries. According to recent studies, factors which are responsible for low yield are unbalanced use of fertilizer, inefficient irrigation practices and late control of pests and diseases. Farmers can get a better yield of sunflower by following these recommendations.
Irrigation and fertilizer application at the time of flowering
Sunflower’s water requirement is low. Farmers usually don’t focus on this aspect due to which per acre yield is reduced. Apply the proper amount of irrigation at critical stages is necessary. No one can deny the importance of water for better growth and development of crops. As all plants uptake the essential nutrients and minerals by using water as a medium.
Considering the growth stages and weather conditions, 3rd irrigation should be applied at the stage of flower bud initiation and at the same time last dose of nitrogen fertilizer should be applied. High temperature and low water availability severely affect seed formation process. 4th irrigation should be applied at the seed formation stage, this occurs 10-15 after flower formation.
Deficiency of water at this stage results in shriveled and thin seeds that would ultimately result in low yield. In hot and dry conditions, light irrigation should be applied when seeds are in the milky stage. This additional irrigation will increase the size and weight of sunflower seeds. To augment the per acre yield balanced and timely use of fertilizers is required.
Harmful pests and their obturation
- Green aphid
It is usually of greenish yellow in color and approximately 3 mm long. Its shape is somewhat triangular and has two black spots on its head. Adults suck leaves from lower side. Green aphid attack is relatively lower on newer and older leaves however commonly seen on intermediate leaves. In case of intense attack, the crop has wilted appearance.
Adult whitefly is small in size, approximately 1.5 mm. Its body is yellowish in color and contains white wings. Its larvae stick on the lower side of leaves. Larvae don’t have wings so that’s why unable to move from their site.
White fly’s adults and larvae both damage the crop by sucking and eventually weakens the crop. It releases sticky fluid from its body on the leaves which further develops into fungus hence process of photosynthesis is badly affected.
At initial life stages, armyworm is light green in color which becomes blackish green in later stages. It contains very prominent lines on both sides of its body and these lines contain black spots on them. Difference between American and armyworm is that it has two black spots on its body while American worm doesn’t bear any black spots on the body.
Its female lay eggs in bulk, from which emerging caterpillars start eating the leaves from the lower side and leave squeeze into thin midribs. Adults make a hole in the leaves and in the severe attack, completely ruin the leaves by eating them.
- American Worm
Newborn American worm has a white body and black head. Though, the adult worm has a dark green color. This worm changes its color according to the crop on which it attacks. American worm damages the leaves and flowers of sunflower. Especially at the initial stage of flower formation, it enters inside the flower and destroys the seeds.
Its adults are of two types. Females are wingless whether male has wings. Female has a white powdery layer on its whole body. Larvae and adults both suck the twigs and leaves. Mealybug also releases gummy fluid from its body on which black fungus grows rapidly hence creates an obstacle in the process of photosynthesis. It creates hindrance in plant growth and the plant becomes completely dry.
Controlling and preventive measures
Many types of research have shown that along with the presence of many harmful insects, many beneficial and predator insects are also found in large amount on sunflower i.e. ladybird beetle, chrysoperla, syrphid fly, trichogramma and pirate bug.
Males of American worm can be captured by sexual pheromones and traps. Keeping in view the number of beneficial insects and pest scouting, pesticides spray against harmful pests should be applied. Avoid pesticides spray during pollination.
- Stem Rot
This disease occurs due to a fungus attack in which black spots appear on the infected site. The outer and inner side of stem attains dark blackish appearance just like coal. Mycelium can be seen in the infested area. Sometimes plant break from the damaged site. Usually, this disease appears before or upon flower formation.
This is also a fungal disease. Small deep spots of brownish and blackish color appear on leaves and the surrounding area of these spots become dry. This fungal disease occurs in the humid season.
- Destroy the infected plants
- Avoid water stress and apply irrigation at regular intervals
- Crop rotation should be practiced for two years
- Avoid excessive watering
After consulting with agriculture expert, apply fungicides and pesticides
Author: Mahmood Ul Hassan, Waqas Hameed, Aqib Hussain Sial, Muhammad Atif Arslan