Identifying marks:
The adults are light brown moths with a wing span of 1.2-2 cm. A dark terminal band characterizes the outer margins of the wings. Larvae are transparent green and measure up to 2.5 centimeters (cm) in length. Adults are attracted to light at night; at daytime, they are mostly found in shaded or grassy areas.
Damage:
Leaffolders inflict damage in the larva stage. Plants are susceptible to attack up to 10 weeks after transplanting (i.e., from seedling to flowering). Infestation usually occurs during early growth stages of the rice crop. The larvae infest the leaves of young plants; they fasten the edges of a leaf together and live inside the rolled leaf. Heavy infestation makes the plant look burnt, sickly, and twig-like.
Life cycle of leaffolder
The eggs are laid singly or in pairs on the young leaves. They are flat, oval, and whitish-yellow. Eggs hatch to larvae in 4-7 days. The transparent green, slender larvae feed inside the folded leaves for 15-25 days before pupation. Adults emerge 6-8 days from pupa. Total life cycle takes 25-52 days. For adult moths, the potential sugar source in the field is the honeydew excreted by planthoppers.
Management options
Cultural
- Flooding the stubble drowns grasshoppers.
- Shaving of bunds kills egg pods.
- Sweeping along the bunds reduces their numbers.
- Adults are sluggish at night, can be picked directly from the foliage, and eaten by people.
Biological
- Small wasps attack grasshopper eggs.
- Parasitic flies, nematodes, and fungal and bacterial pathogens kill nymphs and adults.
- Birds (house sparrow), frogs, and web-spinning spiders are major predators of nymphs and adults.
