After applying aluminum phosphide, when should treatment sites be inspected?

• A. 6-12 hours
• B. 24-48 hours
• C. 3-7 days
• D. 2-3 weeks

Answer: (B)

After fumigation with aluminum phosphide, you want to check the treated area within a 24- to 48-hour window. This timing lets the phosphine gas act long enough to kill exposed pests and for you to assess whether the treatment worked, without letting several days pass and risk pest resurgence or ongoing exposure. Checking too soon (6–12 hours) may miss pests that are still alive, while waiting longer (3–7 days or 2–3 weeks) delays detection of treatment failure and wastes time and resources. In practice, you also verify safety and entry conditions before inspecting, but the practical post-treatment inspection happens around 24–48 hours.