DIFFERENTIAL TRANSMISSION OF STRAINS OF CUCUMBER MOSAIC VIRUS BY APHIDS

Four strains of cucumber mosaic virus were studied in an attempt to determine the reasons for differences in efficiency of their transmission by Myzus persicae. Two strains, Wis. 102 and C-1, were transmitted efficiently from tobacco to tobacco, while strains MCJ and Wis. 14 were rarely transmitted. Wis. 14 was always present in lower concentrations in the plant than the other strains. Strain MCJ was present in as high a concentration as Wis. 102 and C-1, in both epidermal and whole leaf tissue. Tests with leaves systemically infected for different periods showed different trends in transmissibility of virus by aphids. For the two readily transmissible strains, transmission rose rapidly and remained at a relatively constant level. The MCJ strain showed either of two patterns. In some experiments no transmission or extremely low transmission occurred at any time. In others, the virus was transmitted efficiently for a period of 1-3 days, after which it was not transmitted at all. There was no correlation between virus concentration and aphid transmissibility. Wis. 14 was either not transmitted, or was transmitted at an extremely low level. Purified MCJ was transmitted as efficiently as purified Wis. 102 and C-1, indicating that the virus itself is intrinsically transmissible. © 1968.