CGA-20168 (methyl 3-((dimethoxyphosphinothioyl)oxy)-2-methyl- 2propenoate) was applied on corn as emulsion sprays to determine the stability of residues and to assess its ability to control infestations of stored-product insects during a 1-year storage period at ambient temperatures. Although CGA-20168 residues decreased significantly during storage, protection from infestation by stored-product insects was provided throughout the storage period.