The beet leafhopper, Circulifer tenellus (Baker), transmits curtoviruses that cause disease losses to several crops and many weeds in the western United States. While the host plants, life history, and possible migrations have been studied for many years, little is known about differences between leafhopper populations from different areas. Therefore, beet leafhopper populations from California and New Mexico were compared as to their morphology, feeding behavior, and genetics. The crown, wing venation, and male genitalia were indistinguishable among the leafhoppers collected from different locations. Four synonymous mutations were detected in the nucleic acid sequences of the mitochondrial cytochrome oxidase (mtcoi) region of leafhoppers between the states, but not among specimens collected from New Mexico. Feeding preferences of the leafhoppers from the two states differed when presented with cafeteria-style choice tests. With a 20-day feeding period, most (87.5%) of California leafhoppers were found on sugarbeets, Beta vulgaris L., while New Mexico leafhoppers were more evenly distributed on a variety of hosts such as Kochia sp. (46%); sugarbeets (18%); Russian thistle, Salsola tragus L. (15.3%); and red root pigweed, Amaranthus retroflexus L. (12.3%). With a 2-day feeding period, leafhoppers from both states equally chose sugarbeets, reflecting their willingness to settle on sugarbeets over most other hosts. The results suggested that while the beet leafhopper populations were similar morphologically, they showed difference in genetics and host feeding preferences.