One of the most serious insect pests of sugarcane in Reunion Island is the spotted stem borer Chilo sacchariphagus Bojer (Lepidoptera: Pyralidae). Collaborative work between CIRAD and INRA has led to a biological control programme with the exotic egg parasitoid Trichogramma chilonis Ishii (Hymenoptera: Trichogrammatidae). Experience with exotic biological control agents in Réunion suggests that they have not had a significant impact on the populations of C. sacchariphagus in the field. Nevertheless, adaptation over long periods may allow such agents to be used in a revised biological control programme. Recent observations confirm the key role of Trichogramma spp. in biological control of this stem borer, but parasitism levels appear to be lower than previously reported. Current research including morphological and biological studies on Trichogramma spp. are presented and the value of inundative releases in sugarcane are discussed.