14.1 Objectives

Learning Objectives

After completing this chapter, you will be able to:

• Describe the basic concept on how herbicides kill plants, including the 3 herbicide application requirements for them to work.
• Explain 3 ways plants absorb herbicides and what they have in common.
• Describe how herbicide placement gives rise to selectivity.
• Explain how environmental factors can influence herbicide effectiveness, as well as crop safety/injury.
• Understand the influence of weed seedling density on herbicide effectiveness.
• Explain the effect of weed size and age on sensitivity to herbicides.
• Describe the barriers to foliar herbicide absorption and what can be done to improve it.
• Explain processes that degrade herbicides and render them ineffective.
• Define vocabulary words: absorption, translocation, selectivity, contact herbicide; systemic (translocated) herbicide, cuticle, surfactant