The infection of leafhoppers by western X-disease virus. I. Frequency of transmission after injection or acquisition feeding.
Western X-disease virus (WXV) was transmitted to healthy Colladonus montanus Van Duzee by injection of hemolymph or clarified extracts from infected vectors. Virus was first transmitted to healthy celery 11-14 days after the insects were injected with infectious hemolymph. The inoculativity of vectors injected with all inocula reached a peak, then declined rapidly. When tenfold dilutions of extract from infected vectors were injected, the position of the transmission curve for each dilution with respect to the time scale was a function of virus concentration. The latent period in the vector and time of peak transmission were therefore extended when dilutions of extract were injected. Transmission curves obtained from leafhoppers acquiring WXV by feeding on diseased celery were similar to those obtained after injection of a 10(-3) dilution of extract from infected vectors. Percentages of insects transmitting WXV in 2- and 4-day inoculation access periods could be converted to single-day percentages by binomial probability calculations.
Whitcomb
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RF
Division of Entomology and Acarology, University of California, Berkeley, California, USA.
Jensen
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DD
Richardson
J
J