First report of Diuraphis (Holcaphis) frequens as a pest of wheat in Finland

Colonies of Diuraphis (Holcaphis) frequens (Walker) were found on wheat, Triticum aestivum L. in the vicinity of Jokioinen in south-west Finland in summer 1997. The aphid was present in all wheat fields inspected, and was particularly abundant on spring wheat plants of field and plot margins. The aphid was also common on its recognised, host Elymus repens (L.) Gould (couch grass). Damage symptoms, longitudinal chlorotic streaking of tightly rolled leaves, resembled those caused by Diuraphis noxia (Mordvilko), the Russian wheat aphid. Diuraphis frequens appears unlikely to become a serious pest of wheat, and its relative abundance during 1997 may have resulted from particularly hot, dry weather