If weed seeds are in the soil of a field just plowed, choosing which herbicide category is most appropriate?

• A. Pre-emergent herbicide
• B. Post-emergent herbicide
• C. Post-planting herbicide
• D. Herbicide-taller

Answer: (A)

Pre-emergent herbicides are applied to the soil to prevent weed seeds from germinating. Since weed seeds are already present in the soil, using a pre-emergent creates a barrier in the soil that stops those seeds from sprouting as the crop is planted and as conditions become favorable for germination. Post-emergent options target weeds after they have emerged, which isn’t appropriate when the goal is to stop seeds in the soil from germinating. The other choices don’t fit practical category naming for this situation, and “herbicide-taller” isn’t a real category. So, the best choice is a pre-emergent.