Holocyclic Strain of the Spotted Alfalfa Aphid in Nebraska and Adjacent States12

Abstract
The spotted alfalfa aphid, Therioaphis macutata (Buck-preston), has developed what appears to be a holocyclic strain. This strain, identified by its ability to produce sexuales and overwintering eggs during the fall, was first found in Nebraska and now occurs in the adjacent States of South Dakota, Kansas, Colorado, Wyoming, and Iowa. Because of this new overwintering ability, the species is now present throughout the season in areas where it was previously a late-season migrant or totally absent. To date this situation has not increased the economic importance of the species, but it is continuing to spread into colder regions.