This study was conducted to investigate the biology, ecology and control of the stem borer, Chedra fimbristyli, a major pest attacking tikog (cultivated Fimbristylis) in Leyte, Philippines. Life cycle studies have been conducted in the laboratory. There were five larval instars observed and the total larval period lasted for 35-40 days. The larvae underwent a prepupation period of 3 days. Pupation took place on the basal portion of the infested tikog stem. The pupal period lasted for 10 days for both males and females. The adults are small (length of forewings: 4-5 mm), silvery white and live for an average of 5 days. Densities of the stem borer larvae fluctuated throughout the sampling period. Generally, high larval densities occurred when rainfall was low. Pupal counts remained low and stable during the study period. Five plant species (Fimbristylis dichotoma [Cyperaceae], Monochoria vaginalis [Pontederiaceae], Rottboellia cochinchinensis and the two crops Zea mays and Oryza sativa [all Poaceae]) have been identified as hosts of the stem borer in laboratory conditions. A parasitic nematode was the only natural enemy discovered so far. For possible control of the stemborer with botanicals only extracts of three plant species showed slight promise, roots of Denis elleptica (Fabaceae) and Tinosphora rumphii and seeds of Anamirta cocculus (both Mesispermaceae). However, the effect was not comparable to the chemical Azodrin.