Some Aphid Vector-Plant Virus Relationships of the Feathery Mottle Virus of Sweet Potato1

Abstract

A study of the insect vector-plant virus relationships was undertaken with the severe isolate of the feathery mottle virus of sweet potato and the green peach aphid (Myzus persicae (Sulz.). The acquisition threshold period was found to be between 0 and 5 seconds. The inoculation threshold period was in the range of 5 to 10 seconds. Preacquisition starvation experiments revealed that maximum transmission efficiency of the virus could be obtained after 5 minutes of starving. Postacquisition starvation results indicated that as starving time increased, the efficiency for transmission decreased. Results of serial transmission trials indicated that 38 out of 50 aphids, starved and given short acquisition feeding periods, were infective; and these insects infected 115 of the 500 plants tested. Analysis of the data, using the binomial theorem, supported the hypothesis that individual aphids were equally charged with virus. When results of artificial and natural interrupted acquisition feedings were compared, no significant difference in transmission efficiency was found. The green peach aphid, the celery aphid (Aphis apii Theob.), and the melon aphid (Aphis gossypii Glover) were found to be vectors of the virus whereas six other species of aphids tested failed to transmit it.