Role of rice leaf folder larvae (Cnaphalocrocis medinalis) as an alternate host of parasitoid, Trathala flavoorbitalis

A study was conducted in the greenhouse and experimental field of Entomology division, Bangladesh Agricultural Research Institute, Joydebpur, Gazipur during August 2003 to August 2004 revealed that the parasitoid of rice leaffolder (RLF), Trathala flavoorbitalis did not strictly show density dependent and distinct characteristics in T. Aman and Boro seasons. The highest parasitism rate by T. flavoorbitalis on RLF larvae in November was 26% and mid March-April, 28%. The average parasitism rate on RLF was 50.92% and 41.11% in Cage and Micro plot conditions, respectively. In both the conditions, T. flavoorbitalis can effectively parasitize the alternate host, RLF attacking rice. Key words: Parasitoid, C. medinalis, host population, parasitism, T. flavoorbitalis