Some Factors Affecting the Acquisition of Clover Phyllody Virus by the Aster Leafhopper1

Abstract

Transmission of clover phyllody virus (CPV) by the aster leafhopper, Macrosteles fascifrons (Stål), given various acquisition feeds on infected aster plants as adults, increased from 1.5% at 0.5 hour to 61% at 35 days. When the insects were fed as nymphs, transmission increased from 0.6% at 1 hour to 36% at 11 days. A 4-day acquisition feed by nymphs, and 1- and 5-week-old adults resulted in transmission by 23, 52, and 53% of the insects, respectively). When male and female leafhoppers were given acquisition feeds of 3 and 7 days as adults, 4 and 11% of the males and 44 and 44% of the females, respectively, transmitted the virus. After 14-day acquisition feeds, 45% of the males and 63% of the females transmitted. When fed as nymphs, males were only slightly less efficient than females. Transmission by unsexed adult leafhoppers fed on various parts of infected asters was basal stem 60%, upper stem without leaves 54%, upper stem with leaves 46%, flowers 35%, and basal leaf 10%. The availability of virus in infected asters, as determined by the percentage of insects transmitting after a 3-day acquisition feed, remained relatively constant for up to 10 weeks after the appearance of symptoms.