The natural infestation of fruits and stems of Jatropha curcas L. (Euphorbiaceae) by larvae of the pyralid moth Ectomyelois muriscis (Dyar) (Lepidoptera: Pyralidae) is reported for the first time. Populations of E. muriscis on J. curcas were observed in various parts of the state of Chiapas, southern Mexico. Feeding damage by larvae resulted in the destruction of J. curcas seeds. We conclude that this insect is a potential pest of J. curcas cultivation in this region. (C) 2015 Elsevier Ltd. All rights reserved.