Which statement about the pre-harvest interval (PHI) is correct?

• A. PHI is the time after treatment when workers are restricted from entering.
• B. PHI is the pre-harvest interval before harvest.
• C. PHI indicates the maximum number of applications per season.
• D. PHI is the time between re-entry after harvest.

Answer: (B)

PHI is the waiting period required between the last pesticide application and when the crop can be harvested. This interval is specified on the product label to ensure pesticide residues on the harvested crop stay within legal limits and are safe for consumers. It’s crop- and product-specific and can vary with the specific pesticide, crop, and growing conditions.

This concept is not about when workers may enter a treated field after application—that’s the re-entry interval. It’s also not about how many times you can spray in a season, which relates to application limits on the label. And it’s not about any time after harvest for re-entry; PHI specifically concerns the time before harvest. So the statement that PHI is the pre-harvest interval before harvest correctly captures its meaning.