In field experiments, managing for earliness through planting date and varietal maturity reduced tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), densities, insecticide applications, and yield loss. A second experiment highlighted the importance of timely insecticide applications for managing tarnished plant bugs. Differences in fitness parameters were observed between tarnished plant bug populations collected from the Hills and Delta regions of Mississippi. Populations from the Delta region laid more eggs and produced more viable offspring than populations from the Hills. Populations from the Delta reared on cotton developed significantly faster to each life stage than those reared on diet or populations from the Hills region. Overall, tarnished plant bugs survived significantly better on diet than on cotton. Results from these experiments will be important for improving IPM practices for tarnished plant bugs in Mississippi cotton.