Diquat dibromide is an herbicide and plant growth regulator. It is a quick-acting contact herbicide, causing injury only to the parts of the plant to which it is applied.. It is nonselective, meaning that it does not spare 'nontarget' plants from its herbicidal effects. Diquat is referred to as a desiccant because it causes a leaf or an entire plant to dry out quickly. It is not residual, that is, it does not leave any trace of herbicide on or in plants, soil, or water. It is used to desiccate potato vines and seed crops, to control flowering of sugarcane, and for industrial and aquatic weed control.