Major Pests and Diseases in Bottle Gourd: Identification, Symptoms, and Effective Management

Introduction

Bottle gourd (Lagenaria siceraria), also known as lauki, sorakaya, or doodhi, is one of India’s most popular and widely cultivated vegetable crops. Valued for its tender fruits, high water content, and rich nutritional profile, bottle gourd serves as a vital part of the Indian diet. It is a good source of vitamins, minerals, and dietary fiber, and holds significant economic importance for small and marginal farmers due to its high market demand.

However, achieving a healthy yield in bottle gourd cultivation largely depends on effective pest and disease management. The crop is vulnerable to various insect pests and diseases that can severely affect growth, flowering, and fruit quality. Hence, adopting integrated and eco-friendly pest and disease management practices is essential for sustainable production and profitability.

Major Insect Pests of Bottle Gourd

1. Fruit Fly (Bactrocera cucurbitae)

Identification:
Adult flies are reddish-brown with clear wings and black spots. Maggots (larvae) are legless, cream-colored, and feed inside the fruit.

Nature of Damage:
Female flies puncture tender fruits and lay eggs inside. The maggots feed on the pulp, causing soft, rotting patches and fruit drop.

Favourable Conditions:
Warm and humid conditions during fruiting season.

Management:

• Cultural: Collect and destroy infested fruits; use early-maturing varieties; avoid water stagnation.
• Mechanical: Use methyl eugenol traps (10 traps/acre) for male fruit fly attraction.
• Biological: Release parasitoids like Opius fletcheri.
• Chemical: Spray Malathion 50 EC @ 2 ml/litre or Deltamethrin 2.8 EC @ 1 ml/litre at fruiting stage. Avoid spraying near harvest.

2. Red Pumpkin Beetle (Aulacophora foveicollis)

Identification:
Adults are reddish-orange beetles with black spots on their wing covers. Larvae are yellowish-white grubs found in the soil.

Nature of Damage:
Adults feed on leaves, flowers, and tender shoots, leaving irregular holes. Grubs damage roots and underground parts.

Favourable Conditions:
Hot and dry weather during early crop growth.

Management:

• Cultural: Deep ploughing to expose pupae; early sowing to escape heavy infestation.
• Mechanical: Hand-pick beetles in the morning and destroy.
• Biological: Neem-based insecticides (Neem oil 2%) effectively repel beetles.
• Chemical: Spray Imidacloprid 17.8 SL @ 0.3 ml/litre or Lambda-cyhalothrin 5 EC @ 1 ml/litre.

3. Aphids (Aphis gossypii)

Identification:
Small, greenish or blackish soft-bodied insects found in clusters on the underside of leaves and tender shoots.

Nature of Damage:
They suck sap from leaves and stems, causing yellowing, curling, and stunted growth. They also transmit viral diseases like mosaic.

Favourable Conditions:
Dry and warm conditions with dense plant growth.

Management:

• Cultural: Maintain proper spacing and remove infested plant parts.
• Biological: Release ladybird beetles (Coccinella septempunctata) and lacewings.
• Chemical: Spray Dimethoate 30 EC @ 2 ml/litre or Imidacloprid 17.8 SL @ 0.3 ml/litre.

4. Jassids (Amrasca biguttula biguttula)

Identification:
Small greenish leafhoppers that move quickly and suck sap from the underside of leaves.

Nature of Damage:
Leaves curl upward and turn yellowish or bronze; severe infestation leads to defoliation.

Favourable Conditions:
Hot and humid weather.

Management:

• Cultural: Grow resistant varieties; avoid over-fertilization.
• Biological: Encourage natural enemies like spiders and green lacewings.
• Chemical: Spray Thiamethoxam 25 WG @ 0.25 g/litre or Acetamiprid 20 SP @ 0.2 g/litre.

5. Epilachna Beetle (Epilachna vigintioctopunctata)

Identification:
Adults are yellowish-brown with 28 black spots on wing covers. Grubs are yellow and spiny.

Nature of Damage:
Both grubs and adults scrape leaf tissues, leaving a skeletonized appearance.

Favourable Conditions:
Warm, moist weather during vegetative stage.

Management:

• Cultural: Remove and destroy infested leaves.
• Mechanical: Collect and kill beetles manually.
• Chemical: Apply Cypermethrin 25 EC @ 1 ml/litre or Spinosad 45 SC @ 0.3 ml/litre.

Major Diseases of Bottle Gourd

1. Powdery Mildew (Erysiphe cichoracearum)

Symptoms:
White powdery patches appear on upper leaf surfaces and stems, leading to premature leaf drying.

Favourable Conditions:
Warm and dry weather with poor air circulation.

Management:

• Spray Wettable sulfur 0.3% or Hexaconazole 0.1% at early infection.
• Use resistant varieties and avoid excessive nitrogen application.

2. Downy Mildew (Pseudoperonospora cubensis)

Symptoms:
Yellow spots on upper leaf surface with greyish-purple fungal growth beneath. Infected leaves wilt and die prematurely.

Favourable Conditions:
High humidity and cool temperatures.

Management:

• Ensure good field drainage and avoid overhead irrigation.
• Spray Metalaxyl + Mancozeb (0.25%) or Chlorothalonil 0.2% at 10–15 day intervals.

3. Anthracnose (Colletotrichum lagenarium)

Symptoms:
Circular sunken dark brown spots on leaves, stems, and fruits. Infected fruits show black spots and rot.

Favourable Conditions:
High humidity and moderate temperature.

Management:

• Use disease-free seeds and follow crop rotation.
• Spray Carbendazim 0.1% or Mancozeb 0.25%.

4. Fusarium Wilt (Fusarium oxysporum f. sp. lagenariae)

Symptoms:
Yellowing of lower leaves, followed by wilting of vines. Vascular tissues turn brown.

Favourable Conditions:
Warm soil and continuous bottle gourd cropping.

Management:

• Use resistant varieties and well-drained soil.
• Treat seeds with Trichoderma viride @ 4 g/kg before sowing.
• Drench soil with Carbendazim 0.1% if needed.

5. Mosaic Disease (Bottle Gourd Mosaic Virus / Cucumber Mosaic Virus)

Symptoms:
Light and dark green mosaic patterns on leaves, leaf curling, and malformed fruits.

Favourable Conditions:
Dry, warm weather and high aphid activity.

Management:

• Uproot and destroy infected plants early.
• Control aphid population using Neem oil 3% or Imidacloprid 0.3 ml/litre.
• Grow virus-tolerant varieties.

Integrated Pest and Disease Management (IPDM)

Cultural Control:

• Follow crop rotation with non-cucurbit crops.
• Remove weeds and infected debris after harvest.
• Use healthy, certified seeds.

Mechanical Control:

• Install pheromone traps for fruit fly control.
• Use yellow sticky traps for sucking pests.

Biological Control:

• Apply Trichoderma and Pseudomonas fluorescens as seed and soil treatments.
• Encourage natural enemies like ladybird beetles and parasitoids.

Chemical Control:

• Use pesticides only when pest population crosses ETL (Economic Threshold Level).
• Rotate pesticides to prevent resistance.
• Maintain a safe harvest interval (10–15 days) after spraying.

Conclusion

Effective pest and disease management is the backbone of successful bottle gourd cultivation. By integrating cultural, biological, and chemical approaches, farmers can minimize crop losses, maintain soil health, and produce high-quality fruits. Regular field monitoring and the adoption of Integrated Pest and Disease Management (IPDM) ensure long-term sustainability, reduced chemical dependence, and better profitability in bottle gourd farming.