GRAIN APHIDS IN NEW BRUNSWICK: I. FIELD DEVELOPMENT ON OATS

Abstract

Commonly three species of aphids infest oats in New Brunswick, Canada. These aphids are Rhopalosiphum padi (L.), Macrosiphum avenae (Fab.), and Rhopalosiphum maidis (Fitch), named in the order of their abundance. Over a 5-year period (1959–1963 incl.) infestations varied from peaks of less than 1 aphid to 250 aphids per tiller. The aphids infested the crop for approximately 7 weeks, from the time the plants were 3 in. high until the panicles had emerged. When the panicle stage was reached (normally in the fourth or fifth week of the infestation), a winged generation of aphids developed and dispersed from the oats, resulting in an abrupt decline in the population.