Ornamental and Turf Pesticide Applicators Practice Exam

When are winter annual broadleaf weeds best controlled?

1. In early spring

2. In mid to late fall and early winter

3. In late summer

4. In mid-winter

The correct answer is: In mid to late fall and early winter

Winter annual broadleaf weeds are best controlled in mid to late fall and early winter because this timing targets the growth cycle of these weeds effectively. Winter annuals germinate in the fall, establish roots, and then grow until they become dormant in the winter. If control measures, such as pre-emergent herbicides or targeted herbicide applications, are applied during this period, they can effectively disrupt the weed's growth before they become fully established. Controlling these weeds in the fall allows for the herbicides to work on the younger plants when they are most susceptible, preventing them from maturing and setting seed in the spring. This preemptive approach can significantly reduce the weed population for the following growing season. In contrast, early spring is often too late for effective control, as winter annuals have already begun growing vigorously and may be beyond the point of susceptibility to certain herbicides. Late summer is typically focused on managing other types of weeds, and mid-winter would not be practical for applications, as the cold weather can limit herbicide effectiveness and treatment opportunities.