True or False: Pre- and postemergence herbicides are often mixed together to control both existing vegetation and provide residual control of later germinating seeds.

The statement is true because the combination of pre- and postemergence herbicides is a common practice in integrated vegetation management. Preemergence herbicides work by preventing weed seeds from germinating, thus providing a residual control effect that lasts over time. This is particularly useful in areas where you expect weed seeds to germinate after an initial treatment.

On the other hand, postemergence herbicides target existing plants, controlling those that have already germinated. By mixing these two types of herbicides, you can effectively manage both current weed populations and inhibit future growth, creating a more comprehensive control strategy. This method is advantageous in forest sites and other managed areas where maintaining vegetation health is essential, as it helps to reduce competition from weeds while minimizing the need for multiple applications. Combining both types ensures a more efficient use of herbicides and enhances overall pest management effectiveness.