The melon aphid,Aphis gossypii Glov. was extremely abundant and widespread in California during the 1949 season. In some areas very large and destructive populations were encountered, and large quantities of aphicides were used to combat the pest. The seriousness of the infestation afforded ample opportunity to evaluate the effectiveness of several insecticides in controlling the pest on many varieties of melons including cantaloupe, honeydew, Persian, crenshaw, casaba and watermelon.