Gladiolus

Key Points & Important Facts

• Longer day length improves spike quality.
• Planting Time: July–December
• Spacing: 20 × 30 cm
• Corms should be treated with 0.2% Bavistin prior to planting.
• Ethylene chlorohydrin is used to break dormancy of corms.
• Corm dormancy can also be broken by storing at 4–5 °C for 3–4 months.
• Gladiolus is a 7-month crop.
• Hilling (earthing up) is an important cultural operation in Gladiolus.
• Scoring is a very common practice in Gladiolus.
• Preservative Solution: 20% sucrose + 200 PPM HQC
• Gladiolus, popularly called Sword Lily, takes its name from the Latin word ‘Gladius’ because of its sword-shaped leaves.
• It is mainly cultivated in Karnataka, West Bengal, Maharashtra, Punjab, Haryana, Uttar Pradesh, Tamil Nadu, Jammu & Kashmir, Uttaranchal, Delhi, Sikkim, and Himachal Pradesh.
• Widely used in flower arrangements, bouquets, bunches, baskets, and indoor decorations.
• Seeds require 15–20 days to germinate.
• Dormant cormels contain 5–10 times more ABA (Abscisic Acid) than non-dormant ones.
• Cut Spikes Storage Temperature: 1–2 °C for 2 weeks
• Fluoride toxicity is seen on the tip of leaves, absorbed directly from the air.
• Toxicity is due to heavy application of superphosphate and rock phosphate, which contain hydrogen fluoride.
• Geotropism disorder occurs during transportation.
• Short days at the 1–2 leaf stage in Gladiolus lead to blind shoots.

Climate & Soil

• Climate: Subtropical and temperate climatic conditions are suitable. The crop performs well under a temperature range of 16–30 °C. It requires full exposure to sunlight and thrives under long-day conditions with a 12 to 14-hour photoperiod.
• Soil: Well-drained sandy loam soil rich in organic matter with a pH of 6 to 7.

Varieties

• Tropic Sea, Priscilla, Summer Sunshine, Pusa Swarnima, Jackson Ville Gold, KKL.1, Archana, Basant Bahar, Indrani, Kalima, Kohra, Aarti, Arka Kesar, Darshan, Agnirekha, Archana, Bindiya, Shree Ganesh, White Prosperity, Nova Lux, Urovian, Golden Melody, Snow Princess, Silvia, Sansray, Suchitra, Mayur, Punjab Pink Elegance, Punjab Flame, Punjab Glance, Punjab Lemon Delight, Punjab Glad 1.
• Dhiraj: Resistant to Fusarium wilt.
• Sagar: Fragrant variety of Gladiolus.

Mutant Varieties

• Shobha
• Pusa Suwasini (mutant of Wildrose variety)

Cultivation Practices

Propagation

• Commercial propagation is through corms. Cold storage of corms at 3 to 7 °C for 3 months, or treatment with Ethrel (1000 ppm), GA3 (100 ppm), or Thiourea (500 ppm), is adopted for breaking corm dormancy.

Field Preparation and Planting

• The ridges and furrows system is adopted. Beds of size 6 × 2 m are prepared and corms are planted at a depth of 5 cm, adopting a spacing of 40 × 25 cm (88,888 plants/ha) or 25 × 25 cm (1,60,000 plants/ha).

Planting Season

• October for plains and March–April for hills.

Irrigation

• Irrigate at 7–10 day intervals in sandy soils and at less frequent intervals in heavy soils. Irrigation should be withheld at least 4–6 weeks before lifting of corms.

Nutrition

• 120 kg N, 150 kg P2O5, and 150 kg K2O per hectare is recommended, of which 60 kg N and the entire dose of P2O5 and K2O are applied as a basal dose. The remaining N is given in two split doses, 30 and 60 days after planting.

Earthing Up

• When the shoots are about 20 cm high, they are covered by heaping the soil up to a height of 10 to 15 cm. This enables the plants to grow erect despite high winds and rains and suppresses weed growth.

Staking

• Large-flowered varieties should be staked to avoid lodging.

Weed Management

• Weeds compete with crops for water and nutrients and also host insect pests. Gladiolus is a shallow-rooted crop which can easily succumb to weeds. Normally two or three weedings with a gap of 20–30 days are required during the crop period. Weeding can be done either manually using a kurphi/hand hoe or by using herbicides.
• If there is a labor problem, herbicides like Glyphosate / Grammoxone @ 0.6 L / 1000 sq. m can be applied to the soil prior to the planting of corms. Application of herbicides cannot be taken up in standing crop as they injure plants and cause abnormalities in growth.

Harvesting, Grading & Yield

Harvesting of Spikes

• When the first bud shows the color of the variety, harvesting is started. Gladiolus takes 110–120 days to produce spikes. While harvesting, at least four basal leaves should be retained on the plant to ensure proper development of corms and cormels.

Post-Harvest Treatment & Grading

• Soak the stem in water to avoid wilting and lodging of stem and flower. Based on stem length and number of florets, the spikes are grouped into A, B, C, and D grades.

Yield

• 0–2.5 lakh flower stalks per hectare per crop.

Plant Protection

Pests

1. Aphids (Aphis gossypii, Aphis craccivora): Aphids suck sap from tender parts of the plant and infected plants become weak and deformed. They excrete honeydew which attracts sooty mold and ants. Incidence is commonly seen during February and March.
   • Control: Spraying of Malathion 0.1% or Rogor 0.1% at fortnightly intervals.
2. Thrips (Taeniothrips simplex): This is a major pest in gladiolus causing serious damage. Yellow nymphs and black adults damage leaves and spikes by rasping tissue and sucking sap. Affected leaves and spikes develop silver-colored streaks which later turn brown, deform, and dry up. It also attacks corms in storage, making infected corms sticky, shriveled, and producing weak plants.
   • Control: Weekly spraying of Rogor 0.2% or Malathion 0.1%.
3. Cutworms (Agrotis segetum): Incidence is normally observed in the first month of the crop. Eggs of the moth are seen near ground level on plant parts. Larvae feed on emerging shoots and cut plants at ground level during night time. Sometimes they damage underground corms and developing spikes.
   • Control: Spraying of Methyl Parathion 0.05% or Quinalphos 0.05% at fortnightly intervals.
4. Leaf Eating Caterpillar (Spodoptera litura): Egg masses covered with hair are seen on the undersurface of leaves. Early instar larvae feed on the lower surface of leaves by scraping, while mature larvae eat leaves voraciously during night time. Skeletonization of leaves is the main symptom.
   • Control: Spraying of Quinalphos 0.05%, Chlorpyrifos 0.05%, or Carbaryl 0.1% at 10-day intervals. Neem oil 1% or neem kernel extract (NSKE) 4% checks damage caused by early instar larvae.
5. Mealybug: Both nymphs and adults attack corms by sucking sap, causing shriveling and drying of affected corms in severe cases. Incidence starts in the field during dry conditions and carries over to storage. Movement of ants on plants is a sign of mealybug infestation.
   • Control: Application of Methyl Parathion 0.04%, Dimethoate 0.04%, or Acephate 0.1% at fortnightly intervals.
6. Borer (Heliothis armigera): Larvae feed on leaves and unopened buds.
   • Control: Spraying of Thiodan 0.5–0.8%, Endosulfan 0.07%, Methyl Parathion 0.05%, or Ekalux 0.5–0.8% at fortnightly intervals. Neem kernel extract 4% or neem oil 1% can also control the pest.

Diseases

1. Wilt (Fusarium oxysporum f.sp. gladioli): Wilt is a major fungal disease in gladiolus. It is soil-borne and spreads through corms from season to season. High temperature, high nitrogen levels, anaerobic conditions, and CO2 accumulation favor the fungus. Yellowing of older leaves, browning of vascular tissue, and wilting of the whole plant are symptoms.
   • Management: Soil solarization gives good results but is laborious. The best way to control wilt is to plant healthy corms and follow crop rotation. Avoid infected/sick soils. Treat corms in hot water (38–40 °C) containing 2.5 g each of Benlate and Captan per liter for 30 minutes.
2. Corm Rot: Corm rot is a common problem caused by a group of fungi (Fusarium, Curvularia, Stromatinia, and Penicillium spp.). It causes heavy losses, particularly during storage. Anaerobic conditions, airtight storage, and high humidity favor infection. Black, brown, greenish, or yellowish moldy growth on corms is seen. Under poor air circulation, corms rot and emit a foul smell.
   • Management: Hot water treatment (38–40 °C) containing 2.5 g each of Benlate and Captan for 30 minutes. Avoid damage at lifting, improper curing, and dampness in storage.
3. Curvularia Blight: Caused by many fungi, most importantly Curvularia trifolii and Curvularia eragrostidis. Water-soaked oval to elongated brownish spots appear on leaves, sheaths, and petals, later coalescing into dark patches. Moist and warm conditions spread the blight rapidly.
   • Management: Effectively controlled by Mancozeb 0.2% spray at 10-day intervals.

Disorders

Fluoride Injury

• Leaf scorch of gladioli is observed due to the presence of fluorine compounds in the atmosphere which accumulate on the tips of leaves. The injury is associated with heavy application of superphosphate.