In West Central Texas, four herbicides/defoliants that inhibit the production of protoporphyrinogen oxidase (PPO) in the cotton plant performed well as defoliants. The level of desiccation including new growth varies between the products tested. The PPO inhibitors evaluated were carfentrazone-ethyl (Aim® EC from FMC), pyraflufen-ethyl (ET™ from Nichino America), fluthiacet-methyl (Blizzard™ from Crompton Corporation) and flumiclorac-pentyl (Resource™ from Valent USA Corporation). PPO inhibition in cotton results in a quick disruption of cell membranes and a build up of ethylene in the leaf causing it to abscise.