A test was conducted to determine the efficacy or phosphine against insects when applied as aluminum phosphide tablets or pellets to fumigate processed commodities under a polyethylene tarpaulin in a warehouse. At dosage rates of 45 tablets (45 gm. phosphine) or 165 pellets (33 gm. phosphine) per 1, 000 cubic ft., 100per thousand mortality was obtained on rice weevil adults, confused flour beetle adults, saw-toothed grain beetle adults, dermestid larvae, and Indian-meal moth larvae. Four immature rice weevils survived the 45 tablet per 1, 000 cubic foot dosage rate and one survived the 165 pellet dosage rate. Both treatments, however, resulted in an estimated mortality of 99.9per thousand of the immature rice weevil. These results show that phosphine will penetrate processed commodities in commercial packages within shipping cases and will effectively control all stages of stored product insects.