Host Relationships of the Sugar-Beet Root Aphid in California

Abstract

In connection with a comprehensive study of aphids of the genus Pemphigus it was determined that the root aphid commonly found on sugar beets in California and called Pemphigus betae Doane, 1900, was the same species as P. populivenae Fitch, 1859, which forms pouch like galls on the leaves of Populus trichcarpa. Pemphigus populiferae Fitch is closely related 10 if not the same as P. balsamiferae Williams, 1910, a Great Basin species reportedly selecting sugar beets as one of its secondary hosts and also forming pouch like gulls on poplar trees. The economic importance of the sugar-beet aphid in California was reported by Clarke as early as 1903. Lack of information concerning its biological relationships provided the motive for this preliminary study of its primary and secondary host relationships.