Which of the following is true about herbicide application timing?

• A. Timing does not impact effectiveness.
• B. Application is best done in the early evening.
• C. Weather conditions have no impact.
• D. Applying during high temperatures increases effectiveness.

Answer: (B)

Application is best done in the early evening is widely considered true, particularly for many herbicides. This timing allows for better absorption by the target plants due to the cooler temperatures and higher humidity that often accompany the evening hours. During the day, especially in mid-afternoon, the heat can cause increased evaporation rates, which may decrease the amount of herbicide that actually reaches the plant. Additionally, many plants actively take up nutrients and chemicals during the evening as they prepare for nighttime respiration, enhancing the herbicide's effectiveness.

In choosing the timing of herbicide applications, factors such as temperature, humidity, and sunlight all play significant roles. While typically not advisable, applying herbicides at high temperatures can lead to quicker evaporation and reduced control, particularly of non-selective herbicides. Hence, considering timing in relation to these environmental variables is crucial for effective herbicide use.