When are biennial weeds most susceptible to chemical control?

When are biennial weeds most susceptible to chemical control?

• A. During their second year
• B. During their first year
• C. After the first frost
• D. In their dormant phase

Answer: (B)

Biennial weeds have a two-year life cycle, typically characterized by distinct growth stages. In the first year, they primarily grow vegetatively, focusing on leaf and root development. This is the critical time for chemical control because during the first year, biennial weeds are actively establishing their root systems and are more sensitive to herbicides. Applying herbicides during this stage targets the immature plants effectively before they transition into their reproductive phase in the second year. Once they reach their second year, these weeds begin to flower and may produce seeds, making them tougher to manage chemically. Hence, the first year is optimal for control measures as the plants have not yet developed a significant reproductive capacity, and their physiological processes are conducive to herbicide absorption and action.

Biennial weeds have a two-year life cycle, typically characterized by distinct growth stages. In the first year, they primarily grow vegetatively, focusing on leaf and root development. This is the critical time for chemical control because during the first year, biennial weeds are actively establishing their root systems and are more sensitive to herbicides.

Applying herbicides during this stage targets the immature plants effectively before they transition into their reproductive phase in the second year. Once they reach their second year, these weeds begin to flower and may produce seeds, making them tougher to manage chemically.

Hence, the first year is optimal for control measures as the plants have not yet developed a significant reproductive capacity, and their physiological processes are conducive to herbicide absorption and action.