Pink Stem Borer of Rice
Sesamia inferens
📖 Description
Pink Stem Borer of Rice is a major pest of rice and other cereals across the Indian subcontinent, often co-occurring with Yellow Stem Borer but with a broader host range that includes sugarcane, maize, sorghum, and wheat. Adult female moths lay eggs in masses between leaf sheaths and stems. Newly hatched larvae bore into stems, where they feed internally on the central tissue. Larval feeding causes ‘deadheart’ at the vegetative stage and ‘white earheads’ at the reproductive stage. Because of its broad host range, the pest can move between cereal crops throughout the year, maintaining continuous populations. The pink-colored larvae distinguish this species from Yellow Stem Borer (cream-colored larvae) and allow targeted management. The pest is most damaging to late-sown and ratoon rice crops where populations have built up over the season.
⚠️ Symptoms to watch for
- Deadheart (drying of central shoot) at vegetative stage
- white earheads (empty panicles) at reproductive stage
- holes in stems with frass
- broken stems at base
- stunted plants
- yield loss 25-60%
- more damaging to ratoon and late-sown crops
🩹 Treatment
- Install light traps @ 1/ha for adult monitoring
- release Trichogramma japonicum @ 50
- 000/ha
- apply neem cake @ 250 kg/ha as basal
- clip leaf tips to destroy egg masses
- use recommended insecticides when deadhearts appear
🌿 Organic treatments
- Install light traps @ 1/ha for adult monitoring
- release Trichogramma japonicum @ 50
- 000/ha weekly
- clip leaf tips to remove egg masses
- apply neem cake @ 250 kg/ha as basal
- apply Bacillus thuringiensis @ 2 g/L
- handpick egg masses
- apply Metarhizium anisopliae
🧪 Chemical treatments
- Cartap hydrochloride 50 SP @ 2 g/L
- Chlorantraniliprole 18.5 SC @ 0.3 ml/L
- Fipronil 5 SC @ 1 ml/L
- Phorate 10 G @ 10 kg/ha granules at 30 DAT
- Carbofuran 3G @ 25 kg/ha
🛡️ Prevention
- Plant early to escape peak moth activity
- synchronous planting
- remove stubbles after harvest and plough to expose pupae
- clip seedling tips before transplanting
- avoid excessive nitrogen
- control wild grass hosts around fields
- conserve spiders and predatory bugs
- light trapping during moth flights
🪴 Affected plants
- Rice
- Sugarcane
- Maize
- Sorghum
- Pearl Millet
- Wheat
- Some Grasses (Poaceae)
🦋 Natural predators
- Trichogramma japonicum
- Tetrastichus schoenobii
- Spiders
- Carabid Beetles
- Crickets
🌱 Host plants
- Oryza sativa
- Saccharum officinarum
- Zea mays
- Sorghum bicolor
- Triticum aestivum
🔄 Lifecycle
- Female lays 100-300 eggs in masses between leaf sheaths.
- Eggs hatch in 5-8 days.
- Larvae bore into stems and feed for 30-50 days, passing through 5-7 instars.
- Pupation occurs inside the stem or in stubble, lasting 8-14 days.
- Adults live 4-7 days.
- Total life cycle 45-65 days; 4-5 generations per year.
📅 Season
- Year-round, peaks Jun-Oct during Kharif and Jan-Apr during Rabi rice
🔎 Appearance
- Adults are medium-sized, pale yellowish-brown moths with a row of dark spots along the forewing margin.
- Larvae are distinctive pinkish-purple with a brown head, growing up to 30 mm — distinguishable from Yellow Stem Borer by their pink color.
💥 Damage level
- High
🔁 Reproduction rate
- Moderate
🗺️ Geographic regions
- Indian Subcontinent
- Southeast Asia
- East Asia
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