25. Citrus Production Technology

 Citrus

Scientific Name:

Citrus sps. 

Introduction:

    Citrus refers to a group of fruits that belong to the genus Citrus and are known for their juicy, acidic flesh and bright color. Some common examples of citrus fruits include oranges, lemons, limes, grapefruits, and tangerines. These fruits are widely cultivated for their juice, which is commonly consumed as a refreshing beverage, and also used in cooking, baking, and as a garnish for cocktails. Additionally, the zest of citrus fruits is often used to add flavor to a variety of dishes. Citrus is native to subtropical and tropical regions and is now grown all over the world.

Importance of citrus:

Citrus fruits are important for several reasons:

1. Nutrition: Citrus fruits are a rich source of vitamins, particularly Vitamin C, which helps boost the immune system and promotes overall health.
2. CulinaryUses: The acidic juice and zest of citrus fruits are used in cooking and baking to add flavor to a variety of dishes.
3. Beverage Industry: Citrus juice is a popular beverage, either consumed on its own or as an ingredient in mixed drinks, smoothies, and juices.
4. Agriculture: Citrus is a major agricultural crop, providing income and employment for millions of people around the world.
5. Environmental benefits: Citrus trees also provide a habitat for wildlife and help reduce carbon dioxide levels through photosynthesis.
6. Medicinal Properties: The juice and oil from citrus fruits have been used in traditional medicine for their antibacterial and anti-inflammatory properties.

Varieties are grown in Pakistan:

In Pakistan, the main commercial varieties of citrus fruits are:

1. Kinnow: A hybrid of mandarin and orange, Kinnow is the most widely grown and exported citrus fruit in Pakistan.
2. Mosambi: Also known as Sweet Lime, Mosambi is a popular citrus fruit in Pakistan, known for its sweet and juicy flesh.
3. Lemon: Lemons are widely cultivated in Pakistan and used in cooking, baking, and as a garnish for cocktails.
4. Grapefruit: A hybrid of pomelo and sweet orange, grapefruit is grown in Pakistan for both domestic consumption and export.
5. Mandarin: Mandarin is a popular citrus fruit in Pakistan, known for its easy-to-peel skin and sweet flesh.
6. Sherkhana: Valencia late and Salustiana

Major growing areas in Pakistan:

Punjab:           Distt. Sargodha, Sahiwal, Lahore, Sialkot, Jhang, Minwali, Multan,                                    Gujranwala

NWFP:             Mardan, Peshawar, Swat, Swabi, Noshera, Hazzara 

Sindh:             Sukkur, Khairpur, Nawabshah

Baluchistan:     Mekran, Sibi and Kech.

Propagation:

    All improved varieties are propagated via budding on rough lemons or sour oranges. Rootstocks are generally grown through seed, T budding/T grafting is the standard approach of citrus cultivars propagation. Budding can be accomplished throughout spring (Feb-March) and autumn (August-October) whilst bark slips freely from both scion and stock. Bud should be decided on from mature timber or efficient and wholesome timber. In sweet lime propagation via slicing is a common technique.

Soil and climate:

    Citrus bushes may be grown on a wide variety of soils, which includes deep sandy loam, loam, and clay loam. However, they no longer grow properly in very heavy, clayey, sandy, and alkaline or water-logged soils. Citrus fruits and timber are grown in tropical and sub-tropical climates. Temperature is the principal issue affecting, the time of blooming, maturity, production, and fruit quality of citrus.

Pruning:

Pruning is an important aspect of citrus tree care and maintenance. Some reasons for pruning citrus trees include:

• Promote Fruit Production: Pruning helps to remove overcrowded or damaged branches, which can improve the tree's overall health and increase fruit production.
• Maintain Tree Shape: Pruning helps to maintain the tree's desired shape, making it easier to manage and harvest the fruit.
• Encourage New Growth: Pruning can stimulate new growth, helping to replace old or diseased branches.
• Prevent Disease: Regular pruning can help to prevent the spread of disease by removing infected branches.
• Improve Airflow: Pruning can improve airflow through the tree, reducing the risk of fungal diseases and pest infestations.

Water management:

    The desired method of irrigation is a basin spherical for each tree size. There ought to be channel connecting basins so that irrigation of end result trees may be unbiased of the intercropped area among the tree traces that have exclusive water necessities. Increase touchy durations to water shortage are flowering time (Feb/Mar), and fruit setting (Apr/May).

Fertilizers and manures:

• Apply FYMs at the rate of 40 to 80 kg according to tree during the winter season in Dec/Jan before flowering
• Apply 3-4 kg SSP and 1.5 to 2kg of Urea 15-20 days (Jan/Feb) before flowering
• Supply a similar amount of Urea of 1.5 kg in keeping with a tree after fruit setting (Mar/Apr)
• If important 1.5 kg of Potassium Sulphate may be applied at the time of applying FYM
• Watering is essential after each utility of fertilizer.

Pests and their control:

Some common pests of citrus and their control include:

• Aphids: Aphids feed on the sap of citrus trees, causing stunted growth, yellowing of leaves, and a sticky residue on fruit and leaves. Control methods include the use of insecticidal soap, horticultural oil, or the release of natural predators such as ladybugs. 
• Whiteflies: Whiteflies also feed on the sap of citrus trees and can cause the yellowing of leaves and stunted growth. Control methods include the use of insecticidal soap, horticultural oil, sticky yellow cards to trap adults, and the release of natural predators such as ladybugs and parasitic wasps.
• Scale insects: Scale insects feed on the sap of citrus trees and can cause the yellowing of leaves, stunted growth, and reduced fruit production. Control methods include the use of horticultural oil, insecticidal soap, or the release of natural predators such as ladybugs and parasitic wasps.
• Citrus Thrips: Thrips feed on the developing fruit and leaves of citrus trees, causing scarring and deformities in the fruit. Control methods include the use of insecticidal soap, horticultural oil, or sticky yellow cards to trap adults.
• Citrus Leafminer: Leafminers feed on the leaves of citrus trees, causing curled, blistered leaves and reduced growth. Control methods include the use of insecticidal soap or the release of natural predators such as parasitic wasps.

        These are some of the most common pests of citrus and their control in plant pathology. However, the best approach to pest control is to implement an integrated pest management (IPM) program.

Diseases of citrus and their management:

Some common diseases of citrus and their management include:

1.       Citrus canker: Citrus canker is a bacterial disease that causes raised, blister-like lesions on the fruit and leaves. Management includes the removal and destruction of infected plants and the use of copper-based fungicides.

2.       Citrus greening (HLB): Citrus greening, also known as Huanglongbing or HLB, is a serious disease caused by a bacterium that is spread by the Asian citrus psyllid. Management includes the removal and destruction of infected plants, the use of psyllid-resistant rootstocks, and the implementation of an integrated pest management program to control the psyllid vector.

3.       Alternaria rot: Alternaria rot is a fungal disease that causes dark, sunken lesions on the fruit and can lead to fruit rot. Management includes proper sanitation and the use of fungicides such as captan or copper hydroxide.

4.       Phytophthora root rot: Phytophthora root rot is a fungal disease that causes root and crown rot, leading to reduced growth and fruit production. Management includes proper soil drainage, the use of Phytophthora-resistant rootstocks, and the application of fungicides such as metalaxyl or mefenoxam.

5.       Scab: Scab is a fungal disease that causes raised, corky lesions on the fruit and leaves. Management includes proper sanitation and the use of fungicides such as copper hydroxide or sulfur.

Harvesting:

• In Pakistan, the harvesting of citrus fruits usually occurs between November and May, depending on the specific variety. The most common citrus varieties grown in Pakistan include oranges, lemons, and grapefruits.
• The timing of the harvest is determined by several factors, including fruit size, maturity, and color. In general, citrus fruits are harvested when they have reached their maximum size and have developed their full flavor and color.
• To determine when to harvest, growers often examine the fruit for its size, color, and overall quality. Some growers may also test the fruit's sugar content to determine its level of ripeness.
• Once harvested, the fruit is typically washed, sorted, and packed into crates for transport to the market. To ensure maximum quality, the fruit is often handled with care to avoid bruising or damage.

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