Economic Injury Levels for the Rice Leaffolder Cnaphalocrocis medinalis (Lepidoptera: Pyralidae): Insect Infestation and Artificial Leaf Removal

Abstract
Economic injury levels for the leaffolder Cnaphalocrosis medinalis Guenée on rice variety IR36 were determined as based on percentage of leaves damaged and on number of larvae per plant. The economic injury level based on larval density was indirectly estimated by measuring the yield loss at different levels of artificial defoliation and determining the number of larvae per plant required to cause a given percentage of defoliation. The established economic injury levels at the heading stage were 4.2% damaged leaves and 1.3 larva per plant.