Rice Leaf Folder Control

Symptoms

Rice leaf folder (Cnaphalocrocis medinalis) caterpillars fold a leaf longitudinally and stay inside, scraping the green tissue. This leaves white, papery, transparent streaks along the leaf. Folded leaves with feeding marks are easily seen. In heavy attack the field looks scorched and whitish. The adult is a small light brown moth with dark wavy lines on the wings.

Damage

Loss of green leaf area reduces photosynthesis, especially damaging when the flag leaf and upper leaves are affected near flowering. Yield loss is usually moderate but can reach 20 percent or more in severe, prolonged infestation, particularly under high nitrogen and shade.

Organic & cultural control

Avoid excess nitrogen and dense planting which favour the pest. Conserve natural enemies such as spiders and parasitic wasps. Release Trichogramma chilonis where recommended. Spray neem based products at early infestation. A rope dragged across the canopy can dislodge larvae. Light traps help monitor adult moths.

Chemical control

Spray only when the economic threshold is crossed, especially protecting the upper and flag leaves. Recommended molecules include chlorantraniliprole 18.5 SC, flubendiamide, cartap hydrochloride or lambda cyhalothrin used carefully to spare natural enemies. Avoid frequent broad spectrum sprays that kill predators and trigger resurgence. Always follow the product label dose, observe the pre-harvest interval, and consult your local KVK or agronomist before spraying.

Always follow the product label, the recommended pre-harvest interval, and your local KVK or agronomist. Pesticide approvals change, so verify before use.

Prevention

Use balanced nitrogen, avoid very dense planting, keep weeds and shade down, and choose tolerant varieties. Monitor the upper leaves weekly and conserve natural enemies by avoiding unnecessary insecticide sprays.