We surveyed the incidence of Eoreuma loftini (Dyar) (Lepidoptera: Pyralidae) in selected fields in the state of Jalisco, Mexico, in October, 1998, and collected borer larvae from eight sites from August 1998 to March 1999 to measure parasitism and to initiate a colony of the Jalisco fly, Lydella jalisco Woodley (Diptera: Tachinidae). Sugarcane injury from E. loftini larval tunneling was relatively low, ranging from 3-4.4% bored internodes. Bored internodes caused by another stalkborer, Diatraea considerata Heinrich (Pyralidae), ranged from 1.3-6.3%. The extant stalkborer population was almost equally divided between the two species. A total of 3,040 E. loftini larvae were collected, 209 of which were parasitized (6.9%). Lydella jalisco was collected most consistently from the Los Lirios, Ejido Caimanero locality, which yielded 16.1% parasitism (193 fly larvae/1,197 borer larvae). Parasitization by L. jalisco was most successful from mid-August (1998) to mid-October when parasitism was close to 30%. After mid-October, L. jalisco declined and parasitism was predominantly due to the egg-larval parasite Chelonus sonorensis Cameron (Hymenoptera: Braconidae). none