Oryzalin 4 Pro ORYZALIN 4 PRO (41% Oryzalin) ? Generic equivalent for Surflan AS is a preemergence surface applied herbicide for the control of many annual grasses and broad leaf weeds in ornamental plantings, bulbs, ground cover, perennials, established warm-season turf grass, Christmas tree plantations, non-bearing vines and trees and non-cropland and industrial sites. Product may be mixed with Glyphosate to control both existing weeds and weed seeds as they germinate. Oryzalin is applied to soil surface and should be activated within 21 days with rain or irrigation. Rate varies from 1.5 to 3.0 fl. oz. per 1000 sq.ft.