About Lesson
Introduction
Citronella (Cymbopogon winterianus and Cymbopogon nardus) is a perennial aromatic grass cultivated for its essential oil, which is widely used in perfume, soap, cosmetics, and insect repellents. It is an important commercial crop in the aromatic and medicinal plant industry.
Climate and Soil Requirements
Climate:
- Grows best in tropical and subtropical climates.
- Requires warm and humid conditions.
- Optimal temperature: 20-30°C.
- Rainfall: 1500-2500 mm per year.
- Cannot tolerate frost; prefers non-waterlogged conditions.
Soil:
- Grows well in well-drained sandy loam, clay loam, and lateritic soils.
- Prefers a pH range of 5.5-7.5.
- Soil should be rich in organic matter and have good moisture retention.
Varieties of Citronella
Popular Varieties:
- Java Citronella (Cymbopogon winterianus) – High oil content and better yield.
- Ceylon Citronella (Cymbopogon nardus) – Lower oil yield but suitable for specific conditions.
- Manuscript 1 and 2 (OD-19) – High yielding, recommended for commercial cultivation.
Propagation and Planting
Propagation:
- Mainly propagated vegetatively through slips (rooted tillers).
- 4-6 months old clumps are separated into rooted slips and transplanted.
Planting:
- Best time for planting: monsoon season (June-August).
- Spacing: 60 cm x 60 cm (row-to-row and plant-to-plant spacing).
- Seed Rate: 40,000 to 50,000 slips per hectare.
- Planting Depth: 4-5 cm deep.
- Proper irrigation is required immediately after planting.
Nutrient and Fertilizer Management
- Organic Manure: 10-15 t/ha of FYM (Farmyard Manure) before planting.
- Fertilizer Requirement:
- Nitrogen (N): 120-150 kg/ha (applied in split doses).
- Phosphorus (P): 60 kg/ha.
- Potassium (K): 40 kg/ha.
- Top Dressing: Nitrogen is applied in two split doses after each harvest.
- Micronutrients: Zinc and iron application improves growth and oil content.
Irrigation and Water Management
- Requires frequent irrigation during initial establishment.
- After establishment, irrigation is needed once every 7-10 days in dry periods.
- Drip irrigation or sprinkler irrigation is beneficial for water conservation.
- Avoid water stagnation, as it affects root development and oil quality.
Weed and Pest Management
Weed Control:
- Manual weeding is recommended in the early growth stages.
- Mulching with dry leaves or organic matter reduces weed growth and retains moisture.
- Herbicides like pendimethalin (1-1.5 kg/ha) can be applied as a pre-emergence herbicide.
Pest and Disease Control:
- Pests:
- Shoot borer – Controlled by spraying neem-based pesticides or insecticides.
- Grasshoppers and termites – Controlled by organic pest management.
- Diseases:
- Leaf blight and rust – Treated with fungicides like Mancozeb or Copper oxychloride.
- Root rot – Avoid water stagnation and use well-drained soil.
Harvesting and Yield
Harvesting:
- First harvest: 6 months after planting.
- Subsequent harvests: Every 3-4 months (3-4 harvests per year).
- Harvesting should be done when leaves turn slightly yellow for optimal oil yield.
- Method: Cut the grass 15-20 cm above the ground level.
Yield:
- Green herbage yield: 15-20 t/ha per year.
- Oil yield:
- Java Citronella: 80-100 kg oil/ha per year.
- Ceylon Citronella: 60-80 kg oil/ha per year.
Oil Extraction and Quality Improvement
- Method: Steam distillation is used to extract citronella oil.
- Recovery: Oil content varies from 1-1.5% in fresh herbage.
- Storage: Store the extracted oil in airtight containers away from light to preserve quality.
- Main Chemical Constituents: Citronellal, Geraniol, Citronellol, Limonene (responsible for fragrance and insect repellent properties).
Economic Importance and Uses
- Essential Oil Industry: Used in perfumes, soaps, cosmetics, and candles.
- Insect Repellent: Active ingredient in mosquito repellents and sprays.
- Medicinal Uses: Antibacterial, antifungal, and stress-relieving properties.
- Aromatherapy: Used in massage oils and stress relief treatments.
- Intercropping Benefits: Can be grown with legumes, pulses, or short-duration crops.
