The sugarcane stem borers Diatraea saccharalis (Fabricius) and D. indigenella Dyar & Heinrich are common pests of sugarcane crops in Colombia's Cauca river valley (CRV). In 2012, however, D. tabernella Dyar was recorded for the first time in northern CRV and just 1 year later, D. busckella Dyar & Heinrich was detected, also for the first time, in central CRV. The Diatraea outbreak in the CRV was studied, its distribution and population in the region was analyzed, and levels of larval parasitism were observed. During the study of the outbreak, Diatraea species in the CRV were characterized based on the morphology of larval, pupal, and adult stages. Keys to the identification of Diatraea in the CRV based on male genitalia and pupa are provided. Pupal cephalic horns and lateral lobes were discovered as new, reliable characteristics to separate the species at the pupal stage. We suggest biological control program modifications to decrease economic impact and studies at geographically localized levels to better understand the dynamics between the pest species and their parasitoids.