Which herbicide type is applied before the target plants emerge from the soil?

Pre-emergent herbicides are specifically designed to be applied before the target plants, such as weeds, germinate and emerge from the soil. They work by inhibiting seed germination and preventing the establishment of new weed populations. This type of herbicide forms a barrier in the soil, thwarting the growth of seeds that might have been present prior to application. By using pre-emergent herbicides, applicators can effectively manage weed populations before they have a chance to grow and compete with desirable crops or plants.

Other types of herbicides, such as post-emergent, are intended for use after the target plants have emerged, while contact herbicides kill only the parts of the plants they directly touch, and systemic herbicides are absorbed into the plant to kill it from within. Therefore, the timing of application is crucial and identifies pre-emergent herbicides as the correct choice for preventing weed growth before emergence.