What is leaching in relation to pesticides?

Leaching refers specifically to the movement of pesticides through the soil influenced by water. When rainwater or irrigation water moves downward through the soil profile, it can carry dissolved pesticides along with it. This process can lead to the contamination of groundwater or surface water if not managed carefully.

Understanding leaching is crucial for pest control practitioners because it affects how pesticides behave in the environment and their potential impact on non-target organisms and water sources. It is vital to choose substances that have lower leaching potential, particularly when treating areas near water bodies or in sandy soils, where water moves more freely and can transport chemicals further down into the soil or into aquifers.

The other options describe different processes related to pesticides but do not accurately define leaching. Absorption by plants, evaporation, and air movement do not specifically pertain to the downward movement of pesticides through soil due to water.