Molecular Phylogeny of Rice leaf folder (Cnaphalocrocis medinalis)

The rice leaf folder C. medinalis is one of the major pests of paddy, widely distributed in rice growing areas in Asia, Oceania, North east Australia and Madagaskar Leaf folders fold the leaf longitudinally and fasten the margin of the leaf with silk like thread. About eight species of pyralid moths fold or roll leaf of graminaceous plants. Among them, the Cnaphalocrocis medinalis, Marasmia patnalis and Marasmia exigua have only attained the pest status. There are three species of leaf folder prevalent in India of which, C. medinalis is the dominant species. Several outbreaks of C. medinalis have been reported from many Asian countries like India, China, Japan, Korea, Malaysia, Srilanka and Vietnam. In some cases, M. patnalis has been confused with C. medinalis. Understanding the genetic structures of the pest's population may provide important biological information to design IPM strategies for the control of this pest. Hence the present study has made an attempt to reveal the genetic structure of C. medinalis using Cytochrome oxidase subunit I partial sequence. The C. medinalis isolated from Kerala showed 100% similarity with that of Papua New Guinea. The C. medinalis isolated from Australia and China showed 0.22% divergence and C. medinalis isolated from Punjab showed 0.45% divergence with that of Kerala. The C. poeyalis showed 5.75%, C. trapezalis showed 7.86% and Marasmia sp. showed 6.25% divergence from C. medinalis isolated from Kerala.