Texas FFA Nursery Landscape Practice Exam

When is the best time to apply glyphosate for weed control?

1. When weeds are in active growth

2. Just before weed seeds germinate

3. Just before a rain

4. When weed growth is mature

The correct answer is: When weeds are in active growth

Applying glyphosate when weeds are in active growth is the most effective time for several reasons. Glyphosate is a systemic herbicide, which means it needs to be absorbed by the plant to be effective. When plants are actively growing, they are more capable of taking up the herbicide and transporting it throughout their system, which enhances its effectiveness. During active growth, weeds are also producing new leaves and have a robust metabolic activity, allowing glyphosate to inhibit key processes necessary for their survival. This timing maximizes the chance for the herbicide to reach the roots and other parts of the plant, ensuring that it disrupts growth and eventually leads to the plant's demise. In contrast, applying glyphosate just before weed seeds germinate may not effectively control established weeds, as the herbicide targets existing plants rather than seeds. Just before a rain can also lead to a reduction in effectiveness, as rain can wash the herbicide off the leaves before it is fully absorbed. Applying the herbicide when weed growth is mature might seem timely, but by this stage, the plant's nutrient and energy reserves are more developed, potentially allowing it to withstand the herbicide better than in the active growth stage. Therefore, targeting weeds during their active growth