pre-emergent treatments that destroy crabgrass before or shortly after germination, and post-emergent treatments that target and kill the weed itself. Some products claim to do both, and in many ...
Pre-emerge herbicide must be applied before the weed seeds germinate. An example of a pre-emerge product is Prowl H2O. This herbicide is used to control Crabgrass in Bermudagrass hayfields.