AI: 40.7% Prodiamine. Barricade is a pre-emergence herbicide that offers low-rate, season long control of more than 30 grassy and broadleaf weeds, including crabgrass, goosegrass and Poa annua. Barricade offers the widest possible window for keeping turf weed-free, allowing for applications as early as January - and a single application lasts an entire season. Plus, Barricade herbicide will not stain fences or other landscape features.