Tecia solanivora (Lepidoptera: Gelechiidae) (Povolny 1973), is the most important insect pest of potato (Solanum tuberosum L.) in Central and South America, and Spain. The species was recently reported in Mexico, demonstrating the power of invasion by this insect. In Peru, the insect is quarantined, and could become a damaging pest in America. Larvae attack potato tubers, causing economic loss of 50 to 100%. We used eight microsatellites in 152 individuals from Antioquia (North), Boyacá (Center), Nariño (South), and Norte de Santander (East), Colombia, and found T. solanivora genetically different based on an AMOVA test (F_ST = 0.094, P < 0.01, R_ST = 0.175, P < 0.01). The differentiation was supported by Bayesian analysis where we estimated K = 2. The outcome suggests populations from Antioquia and Boyacá are genetically similar whereas populations from Nariño and Norte de Santander differ because of geographical separation from other regions. We found T. solanivora had not undergone a recent bottleneck effect suggested by other authors. On the contrary we found that this species has undergone recent population expansion in the country. We suggest that movement of potatoes caused genetic homogenization. Movement occurs from Boyacá where most potatoes are produced, to the rest of Colombia.