Coelaenomenodera minutaUhlmann is one of the major pests of the oil palm,Elaeis gulneensisJacq, in West and Central Africa. An epidemic by this leaf miner pest reduces oil palm yields by as much as 30%. A leaf miner outbreak on oil palms at Lobe (Cameroon) was first recorded in 1972. Since then over $US200 000 were spent annually on insecticides to eradicate the pest, but it was never brought under permanent control. Results indicate that leaf miner parasites were either rare or missing, and that the fauna of theCrematogasterspecies was very poor. These findings led to the conclusion that the natural enemies of the pest were under pressure of insecticides. The deployment ofCrematogasterspecies led to a decline of the leaf miner pest population in all treated fields. The reduction in the pest population was mainly due to the destruction of the larval galleries resulting in the exposure of larvae to unfavourable temperatures, heavy rains and attacks by parasites and predators. A system for monitoring and keeping the pest population below threshold level by the use ofCrematogasterspecies proved effective, and it is recommended in young palm plantings even in areas where the pest is endemic. This control method will lead to significant cash savings and the preservation of the environment.