How can irrigation timing after pesticide application affect efficacy?

• A. Irrigation after spraying should always be done immediately for best efficacy.
• B. Irrigation timing does not affect product performance.
• C. Irrigation too soon can wash away the product and reduce efficacy.
• D. Rainfast requirements are unrelated to irrigation timing.

Answer: (C)

After applying a pesticide, you want the product to stay on the target site long enough to do its job. Irrigating too soon can wash away the spray from leaf surfaces or dilute it, so less active ingredient remains where pests contact it. This reduces contact and effectiveness, especially for products that rely on staying on the foliage to work. Labels often specify a drying period or a minimum wait before irrigation or rainfall to let the product adhere and begin acting. Some products meant to move into the soil may require irrigation to activate, but the general idea is that rushing irrigation can undermine efficacy by removing or diluting the product.