Cnaphalocrocis medinalis, the rice leafroller, is a species of moth of the family Crambidae. It is found in south-east Asia, including Hong Kong, Sri Lanka, Taiwan, Thailand and most of Australia.

This moth typically has a wingspan of approximately 16 millimeters.

Its larvae are recognized as pests of various crops, including Oryza sativa, Zea mays, and Triticum, Saccharum and Sorghum species.

The adult moth is characterized by its vibrant yellow or straw coloration, with distinct wavy lines visible on its forewings and hindwings. Eggs are usually laid individually or in groups on the undersides of leaves, appearing scaly and white. A female moth can lay around 56 eggs, with an incubation period lasting between 4 and 8 days. Larvae go through 5 to 6 instars over a period of approximately 22 to 23 days before pupating within folded leaves for about 6 to 7 days. Fully grown caterpillars are green and measure around 16.5 millimeters in length. The entire life cycle of this moth spans about 5 weeks.

Throughout its life stages, the rice leafroller can cause significant damage to crops. Newly hatched caterpillars initiate damage by cutting leaf edges and folding them. In the case of young seedlings, they may fold multiple adjacent leaves and consume the green tissue, leaving affected leaves with a whitish appearance. A single caterpillar can damage numerous leaves, leading to reduced plant vigor and eventual crop yield loss, which can range from 10% to 50%. This pest poses a more severe threat during the boot leaf stage of crop development.

...