What irrigation restriction applies to 2,4-D treated water?

• A. It can be used on all crops
• B. Do not water certain plants with treated water until after 7 days or concentration ≤ 100 ppb
• C. No irrigation restrictions
• D. It is safe to water within 24 hours

Answer: (B)

When water has been treated with 2,4-D, the restriction is about preventing harm to sensitive plants and reducing residue in crops. The rule allows two safe options: either wait at least seven days after treatment before using that water for irrigation on certain plants, or use the water only if the 2,4-D concentration is at or below 100 parts per billion. This dual approach targets both timing and concentration to minimize uptake by crops and avoid phytotoxic effects. This is why the choice stating a seven-day wait or a low concentration threshold is the correct guidance. The other options imply no restrictions, or immediate watering, which could expose plants to damaging levels of 2,4-D.