Lawn & Garden Products LG4300 Monterey RTU Sucker Stopper, 16-Ounce Is made from the plant growth regulator napthaleneacetate (NAA) This product is widely used in commercial agriculture to prevent suckers and as a thinning agent on fruit trees Sucker-Stopper RTU is used to prevent suckers and water sprouts on apples, pears, olives, non-bearing citrus and woody ornamental plants