Paraquat, a nonslective contact herbicide, has been evaluated in tankmix and sequential applications for cotton (Gossypium spp.) harvest aid. Paraquat was tested at rates ranging from 0.07-0.25 lb ai/A with rate depending on application timing. Proper defoliation is dependent on crop maturity and various environmental conditions.

Data were collected from 1987-1989 throughout the southern cotton growing region from Georgia to Texas. In the Southwest, results show higher rates of Paraquat can be used effectively either alone and tankmixed with Def, Dropp or Prep treatments. In this cotton producing are, consistent results were achieved with sequential treatments. Studies conducted in the Midsouth and Southeast were conducted with tankmixtures of Paraquat plus Def, Prep or Folex. Tankmix results were erratic and very dependent on plant and environmental conditions. More consistent results have been achieved with sequential application of Paraquat alone or tankmixed with Prep following an initial application of a standard defoliant. Overall, Paraquat provides and economical and effective alternative for cotton defoliation.