Determination of Zinc Phosphide Residues in Corn ( Zea mays ) Grain, Fodder, and Forage

Zinc phosphide (ZN3P2) is an acute rodenticide. One of its current uses employs application as a grain bait or pellet at the time of planting to reduce agricultural losses by field rodents. To mitigate rodent induced losses to corn, we hoped to expand the approved uses of zinc phosphide to include corn applications. After determining acceptable efficacy, we conducted a study to determine if potentially hazardous zinc phosphide residues in corn would result from this use. A field study was conducted in 5 corn growing states to provide samples for residue analysis of corn treated with zinc phosphide.