South Dakota has recently experienced a significant increase in the proportion of acres treated with insecticide. Unfortunately, data on insecticide usage by crop at the county level is not available. The following case study seeks to uncover the reasons for this increase by analyzing county-level data in South Dakota with a fixed effects panel regression. The study links the proportion of acres planted for a specific crop to the proportion of total acres treated with insecticide. This approach provides insight on how changing cropping patterns in South Dakota have influenced insecticide use.