Why should you avoid excessive irrigation after spraying pesticides?

• A. Excessive irrigation after application helps distribute the pesticide evenly.
• B. After application, you can irrigate as much as you want.
• C. Avoid excessive irrigation after application to protect beneficial microorganisms and prevent spread of residues.
• D. Irrigation has no effect on pesticide performance.

Answer: (C)

After spraying pesticides, residues should stay where they were applied so they can act on the target pests without spreading uncontrolled. Pouring too much irrigation water can wash residues off the treated area, move them into runoff or off-target zones, and push them deeper into the soil. This not only reduces the pesticide’s effectiveness where it’s needed, but can raise environmental risks by spreading residues beyond the intended area. Heavy irrigation can also harm beneficial microorganisms in the soil by washing away or flushing them, which disrupts natural pest suppression and nutrient cycling. So, avoiding excessive irrigation helps keep residues in place and protects soil biology.