Rice Leaf Folder
Cnaphalocrocis medinalis
Sap-Sucking Insects High Risk Wingspan 15-18 mm
📖 Description
Rice Leaf Folder has emerged as a major pest across South and Southeast Asia with the spread of high-yielding rice varieties and intensive cultivation. The caterpillars fold leaves by stitching the edges with silk threads and feed by scraping the green tissue inside the fold, leaving white translucent patches. Heavy infestation can defoliate entire fields, significantly reducing photosynthesis and grain yield. Outbreaks are often triggered by excessive nitrogen application and the destruction of natural enemy populations through broad-spectrum insecticide use.
⚠️ Symptoms to watch for
- Longitudinal folding of leaves stitched with silk
- white and transparent feeding patches inside folded leaves
- drying of leaf tips
- reduced photosynthesis
- stunted plants in heavy infestation
🩹 Treatment
- Release Trichogramma japonicum cards @ 50
- 000/ha at flowering
- apply neem oil 5ml/L
- use light traps to catch adult moths
- apply recommended insecticides when damage exceeds 10% folded leaves
🌿 Organic treatments
- Release Trichogramma japonicum @ 50
- 000/ha 3 times at weekly intervals
- apply Bacillus thuringiensis (Bt) @ 1 g/L
- spray neem oil 5ml/L with sticker
- set up light traps @ 1/ha
- apply Metarhizium anisopliae
🧪 Chemical treatments
- Chlorantraniliprole 18.5 SC @ 0.3 ml/L
- Flubendiamide 39.35 SC @ 0.5 ml/L
- Cartap hydrochloride 50 SP @ 2 g/L
- Triazophos 40 EC @ 1.5 ml/L
🛡️ Prevention
- Plant resistant varieties (Pusa 1121, Samba Mahsuri)
- avoid excessive nitrogen
- balanced fertilizer use
- conserve spiders and predatory bugs
- remove grassy weeds that harbor larvae
- light trapping during peak moth activity
🪴 Affected plants
- Rice
- Wild Rice
- Sugarcane
- Sorghum
- Maize
- Grasses
🦋 Natural predators
- Spiders
- Mirid Bugs
- Coccinellid Beetles
- Trichogramma Wasps
- Ground Beetles
🌱 Host plants
- Oryza sativa
- Oryza rufipogon
- Echinochloa crus-galli
- Cyperus rotundus
🔄 Lifecycle
- Female moth lays 50-100 eggs singly on the underside of leaves.
- Eggs hatch in 4-7 days.
- Larvae fold leaves and feed for 15-25 days, passing through 5 instars.
- Pupation occurs inside the folded leaf and lasts 6-10 days.
- Adults live 5-10 days.
- Total life cycle completes in 25-45 days; 4-6 generations per year.
📅 Season
- Active Jul-Oct during Kharif rice, peak at tillering to booting stage
🔎 Appearance
- Adults are small yellowish-brown moths with three dark wavy lines on each forewing and a dark margin on hindwings.
- Larvae are pale green with a translucent body, growing up to 20 mm.
- They fold rice leaves by stitching the margins with silk.
💥 Damage level
- High
🔁 Reproduction rate
- Fast
🗺️ Geographic regions
- Indian Subcontinent
- Southeast Asia
- East Asia
- Pacific Islands
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