Numerous reports have been received from growers in Manitoba and Saskatchewan that the sweetclover weevil, Sitona cylindricollis Fahr., greatly reduces sweet clover seed yields by feeding on the seed or by causing it to drop. It is known that weevil populations are often very high in clover fields that are left for seed. To determine the amount of damage that might be caused to seed by the weevil, a number of tests were conducted in 1951 and 1952.