Potato Tuber Moth
Phthorimaea operculella
📖 Description
Potato Tuber Moth (PTM) is a major pest of potato and other solanaceous crops across the Indian subcontinent, causing damage both in the field and in storage. Larvae mine leaves of potato and tomato plants, then bore into developing tubers in the field. In storage, larvae tunnel through tubers, causing rotting and complete loss within 2-3 months. PTM is particularly devastating in regions where potatoes are stored in traditional ambient-temperature stores rather than cold stores. Field management relies on proper hilling (mounding soil around plant base to keep tubers covered) and timely harvest. Storage management requires sorting infested tubers, cool storage, and application of biological agents like Bacillus thuringiensis or granulosis virus dust.
⚠️ Symptoms to watch for
- Leaf mines in potato and tomato foliage
- bore holes on tubers with frass
- tunnels inside tubers
- rotting of infested tubers in storage
- complete tuber loss in storage in 2-3 months
- yield loss 30-100%
🩹 Treatment
- Apply pheromone traps @ 8/ha
- mound soil around plants to prevent tuber access
- spray Bacillus thuringiensis @ 2g/L
- use recommended insecticides at tuber formation
- sort and discard infested tubers before storage
🌿 Organic treatments
- Install pheromone traps @ 8/ha for mass trapping
- mound soil around plant base to prevent tuber access
- apply Bacillus thuringiensis @ 2 g/L
- apply granulosis virus (PtGV) @ 50 g/ha
- spray neem oil 5 ml/L
- sort and discard infested tubers before storage
- store tubers in cool dry conditions with neem leaves
🧪 Chemical treatments
- Cartap hydrochloride 50 SP @ 2 g/L
- Indoxacarb 14.5 SC @ 1 ml/L
- Spinosad 45 SC @ 0.5 ml/L
- Emamectin benzoate 5 SG @ 0.5 g/L
- Chlorantraniliprole 18.5 SC @ 0.3 ml/L (spray at tuber initiation)
🛡️ Prevention
- Plant certified seed tubers
- mound soil around plant base to keep tubers covered
- harvest promptly at maturity
- sort and discard infested tubers before storage
- store tubers in cool (10-15°C) dry conditions
- fumigate storage with Bacillus thuringiensis dust
- avoid leaving tubers in the field after harvest
- plant early to escape peak moth activity
🪴 Affected plants
- Potato
- Tomato
- Tobacco
- Eggplant
- Other Solanaceae
🦋 Natural predators
- Trichogramma pretiosum
- Copidosoma koehleri
- Predatory Bugs
- Spiders
- Ants
🌱 Host plants
- Solanum tuberosum
- Solanum lycopersicum
- Nicotiana tabacum
- Solanum melongena
🔄 Lifecycle
- Female lays 100-200 eggs on leaves, stems, or exposed tubers.
- Eggs hatch in 4-7 days.
- Larvae mine leaves or bore into tubers, feeding for 10-20 days, passing through 4 instars.
- Pupation occurs in soil, debris, or storage, lasting 6-12 days.
- Adults live 7-15 days.
- Total life cycle 20-40 days; 6-8 generations per year in field, continuous in storage.
📅 Season
- Year-round, peaks Oct-Mar during Rabi potato season and Apr-Jul in storage
🔎 Appearance
- Small greyish-brown moths with dark speckles on forewings and fringed hindwings.
- Larvae are greenish-white with a brown head, growing up to 12 mm, found mining inside leaves and boring into potato tubers.
💥 Damage level
- High
🔁 Reproduction rate
- Fast
🗺️ Geographic regions
- Indian Subcontinent
- Worldwide Tropics and Subtropics
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