The purpose of this study was to monitor tobacco thrips populations during the early spring in Georgia and to determine the role of brachypterous tobacco thrips in epidemics of tomato spotted wilt virus (TSWV). Potted peanuts were placed into fields at four locations in south Georgia throughout the spring of 2000 and 2001. During March 2001, half of all potted peanuts were covered with exclusion/inclusion cages. Tobacco thrips were collected from terminals and flowers on a weekly basis and were identified as macropterous or brachypterous. Nonstructural protein enzyme-linked immunosorbent assay (ELISA) was performed on individual thrips to determine the proportion of brachypterous and macropterous viruliferous thrips in the population. Macropterous thrips were more abundant than brachypterous thrips, except at the Coffee County location during late February and early March. Peaks in thrips abundance and percentage of viruliferous thrips shifted approximately 2 wk later for 2001 than for 2000 at the Tift County location. In laboratory transmission experiments, no difference was found in the ability to transmit TSWV for the two wing morphs. Macropterous thrips appear to be more capable of colonizing and subsequently transmitting TSWV to newly emerged crops. Therefore, it appears that brachypterous tobacco thrips may help to perpetuate the disease cycle of TSWV by harboring the virus over the winter, and by keeping inoculum in the population until temperatures rise and the percentage of macropterous thrips in the population increases.