Tag: citrus

• Citrus crops are prone to various nutrient deficiencies, physiological disorders, pests, and diseases.
• Proper identification and management are crucial for healthy growth and high yield.
• Integrated management practices combine cultural, chemical, and biological methods.

• Sudden temperature changes and moisture stress.
• Cracking may be radial or transverse.
• Secondary infection by Aspergillus, Fusarium, or Alternaria possible.

Management:

• Apply light irrigation at frequent intervals.
• Apply potassium during fruit development.

• Juice vesicles become hard, enlarged, and opaque grayish.
• Pulp density increases; juice has more minerals, less carbohydrate and organic acid.
• Lignification of juice cells forms sclerenchyma.

Causes:

• High humidity, temperature fluctuations, excess nitrogen, large fruit size, susceptible rootstocks.
• Young trees and mandarins on Jatti Khatti rootstock are more prone.

Management:

• Avoid excess moisture.
• Spray lime (20 kg in 450 L water).
• Spray zinc (0.5%) and copper (0.5%).

• Exposed fruit develops yellow patches, turning brown and hard.
• Inner portion becomes desiccated and discoloured.
• Fruits malformed, low juice content, may drop; leaves turn brown.

Management:

• Spray lime solution (20 g/L) before summer.
• Regulate irrigation to reduce temperature.
• Mulch tree basins.

• Stunted growth, leaf mottling, yellowing, and shedding.
• Excess flowering, poor fruit set, sun blotching of fruits.

Causes:

• Calcium carbonate or clay in soil, rootstock-scion incompatibility, salinity, waterlogging, poor orchard management.

Management:

• Ensure proper drainage and orchard management.
• Use resistant rootstocks and disease-free budwood.

• Spray dimethoate 2 ml/L + neem oil 3%.

Leaf Caterpillar:

• Apply endosulfan 2 ml/L for moderate to severe infestation.

Sucking Pests (Whitefly):

• Spray quinalphos 2 ml/L.

Nematodes:

• Apply carbofuran 75 g/tree or Pseudomonas fluorescens 20 g/tree.

• Prune dried twigs and spray 0.3% copper oxychloride.

Scab:

• Spray 1% Bordeaux mixture.

Tristeza Virus:

• Remove and destroy infected trees.
• Spray monocrotophos 1 ml/L to control aphid vectors.
• Use pre-immunized seedlings for planting.

• Acid lime starts bearing from the 3rd year after planting.
• Main crop harvested at different times across regions; average yield is 20–25 kg/tree/year.
• Treat fruits with 4% wax emulsion and pre-pack in 200-gauge polythene bags (1% ventilation) to extend shelf life over 10 days.
• Store limes at 18°C for best results.
• Low-cost storage tanks with double-layer brickwork and wet sand interspace can be used for storage.

• Combine cultural, chemical, and biological methods for sustainable citrus production.
• Regular monitoring and early detection of disorders, pests, and diseases.
• Use resistant varieties and healthy planting material.
• Maintain balanced nutrition and proper irrigation.
• Adopt proper pruning, sanitation, and post-harvest handling.

• Citrus spp. belong to the family Rutaceae.
• Includes oranges, lemons, limes, pummelo, and grapefruit.
• Originated in tropical and subtropical Southeast Asia.
• Third most important fruit group in India after mango and banana.

• Acid group: Acid lime (C. aurantifolia), Lemon (C. limon), Citron (C. medica), etc.
• Orange group: Sweet orange (C. sinensis), Sour orange (C. aurantium).
• Mandarin group: C. reticulata, C. unshiu, C. deliciosa, Kinnow.
• Pummelo and grapefruit group: Pummelo (C. grandis), Grapefruit (C. paradisi), Kumquat (Fortunella sp.).
• Hybrids: Citrange, Tangelo, Citrangequat, used mainly as rootstocks.

• Best grown in subtropical climates, 500–1500 m MSL elevation.
• Optimal rainfall: 150–250 cm/year; mild winters preferred.
• Ideal soil: Medium/light loam, pH 5.5–6.5, well-drained.
• Acid lime prefers pH 6.5–7.0; sensitive to frost.

• Kodai Orange (C. reticulata): Vigorous, small, loose rind, heavy seeded.
• Nagpur Santra (C. reticulata): Leading commercial mandarin, fine texture, juicy, matures Jan–Feb.
• Coorg Mandarin (C. reticulata): Medium-large, bright orange, regular bearer.
• Satsuma Mandarin (C. unshiu): Japanese, seedless, thin rind, excellent quality.
• Kinnow (King × Willow leaf): Hybrid, high yield, export potential.
• Khasi Mandarin: North-East India, excellent quality, polyembryonic seeds.

• Seed propagation: Used for most mandarins; select true-to-type, healthy seeds.
• Vegetative propagation: T-budding on rootstocks like Rangpur lime, Cleopatra, Rough lemon, Troyer citrange.
• Budded plants bear earlier and are more uniform.
• Rootstocks selected for disease resistance and soil adaptability.

• Planting season: May–June and September–October (monsoon period).
• Spacing: 6 × 6 m for most mandarins; 5–6 m for acid lime.
• Pit size: 75 × 75 × 75 cm, filled with FYM, sand, and topsoil.
• High-density planting possible for Kinnow using Troyer citrange rootstock.

• Train trees to single stem with 4–6 main branches.
• Remove water shoots, rootstock sprouts, and laterals up to 45–50 cm height.
• Prune bearing trees after harvest to remove dead, diseased, and weak branches.
• Root pruning sometimes used for crop regulation.

• Mandarins may flower 1–3 times/year (Ambe, Mrig, Hast Bahar).
• Bahar treatment: Expose roots and withhold water to induce rest and synchronized flowering.
• Not recommended for light soils or North India.

• Apply FYM and NPK fertilizers in two splits (June and October).
• Micronutrients: Zn, Mn, Fe, Mg, B, Mo required; avoid excess Na and Cl.
• Apply lime/dolomite in acidic soils once every 2–3 years.
• Foliar sprays of micronutrients during new flushes improve growth.

• Young plants require regular irrigation, especially during dry spells.
• Mandarins: Water at 10–15 day intervals in winter, 5–7 days in summer.
• Avoid waterlogging; citrus is sensitive to excess moisture.
• Water should be free from salts.

• Weeds compete for nutrients and water, especially in young orchards.
• Pre-emergence herbicides: Diuron (5 kg/ha), Terbacil (4.5 kg/ha).
• Post-emergence: Atrazine (5–6 kg/ha), Glyphosate (5 L/ha).
• Intercropping with legumes (pea, cowpea, blackgram) is beneficial during pre-bearing years.

• 2,4-D (20 ppm) or NAA (30 ppm) sprayed at flowering and marble stage increases fruit retention.
• Improves fruit set and reduces premature fruit drop.

• Budded plants bear in 3–5 years; seedlings in 5–7 years.
• Yield: 15–20 t/ha/year; 1000–1500 fruits/tree/year at full bearing.
• Harvest when fruits are full-sized, colored, and have optimal sugar-acid blend.
• Use clippers or secateurs to avoid skin damage.

• Grade fruits by size and appearance; pack in wooden boxes or CFB cartons.
• Store at 8–10°C, 85–90% RH for best shelf life.
• HDPE/poly bags with ventilation extend storage life of Kinnow and Nagpur Santra.
• Waxing and neem leaf extract reduce post-harvest losses.

• Citrus requires careful varietal selection, proper soil, and climate management.
• Judicious nutrient and water management are essential for high yield and quality.
• Integrated weed, pest, and disease management improve orchard health.
• Proper post-harvest handling ensures better market returns.