COMPARISON OF A YELLOW FORM OF THE GREEN PEACH APHID, MYZUS PERSICAE (SULZER), AND A GREEN FORM OF THE TOBACCO APHID, MYZUS NICOTIANAE BLACKMAN, COEXISTING ON GREENHOUSE POTATO IN NEW BRUNSWICK

Abstract A dark green aphid was isolated from a greenhouse colony of green peach aphid, Myzus persicae (Sulzer), in Fredericton, N.B. The green aphid was shown to conform taxonomically and biologically to the recently named species Myzus nicotianae Blackman, except for its rare production of alatae. It is reported for the first time on greenhouse-grown potato where its population development is similar to that of the yellow holocyclic M . persicae from the same colony. The vector efficiency of the green and yellow aphids for potato virus Y 0 is similar. The yellow aphid tends to be more susceptible to insecticides than the green aphid. Myzus nicotianae was not found in aerial aphid samples taken in New Brunswick in 1967 and 1987.