Ornamental and Turf Pesticide Applicators Practice Exam

What is a common effect of post-emergence herbicides when they contact green bark?

1. Stimulates growth

2. Causes no harm

3. Can damage plants

4. Enhances photosynthesis

The correct answer is: Can damage plants

Post-emergence herbicides are designed to control weeds after they have emerged from the soil, but they can have negative effects on non-target plants, particularly when they come into contact with non-target tissues like green bark. When these herbicides are applied, the active ingredients can be absorbed by the plant through its tissues, which can lead to physiological disruptions. This can manifest as injury or damage to the plant, leading to symptoms such as leaf curling, chlorosis, or even dieback. Unlike other effects that might suggest a beneficial impact on plant growth or health, the reality is that post-emergence herbicides can interfere with natural metabolic processes and overall plant vigor, causing detrimental effects. This highlights the importance of careful application methods and practices to avoid incidental contact with desirable plants, especially in ornamental and landscaping scenarios.