Bonide Sucker Punch, available as a concentrate or premixed, contains the synthetic plant growth regulator ethyl-1-naphthalene acetate or NAA. The natural form, auxin, is a plant hormone that plays a role in everything from stem elongation to root formation. In very small amounts, NAA stimulates root formation in cuttings; it is often a component of both commercial and over-the-counter root products. In higher concentrations it inhibits the formation of roots. Other uses of NAA include fruit thinning (citrus) and retention (mango), as well as sprout suppression in a number of fruit and ornamental species. It is safe to use – follow the recommendations on the label. Similar products with NAA, which are available under other trade names, are also on the market. And while a number of herbicide products do the job, this option is better for the environment.