Effect of the Pea Aphid, Acyrthosiphon pisum (Harr.) (Homoptera: Aphididae), on Yields of Alfalfa Hay on Irrigated Land

Abstract

Although there are many reports on the control of the pea aphid and its effect on the yield of peas, few are available on the effect of the aphid on the yield of alfalfa hay, particularly on irrigated land. The experiments of Cook and App (1956) and Franklin (1953) were done under climatic and edaphic conditions different from those encountered in southern Alberta. Outbreaks of the aphid occur only occasionally in Alberta, but in 1957 it was very abundant in some irrigated alfalfa fields. This is a report on the effect of the aphid on yields of alfalfa hay in an irrigated area in southern Alberta.