Seventy-two potato tubers of 106 tested from plants exposed 1 year in a field were found infected with potato virus S (PVS) in different tests. Ninety-three percent of these were detected by tuber juice inoculation to Nicotiana debneyi Domin. and 90% by serology of 30-cm plants grown from an eye of such tubers. Sap inoculation to N. debneyi of the same young plants proved to be 96% efficient in detecting the virus, and serological tests at bloom stage were the most efficient of all the tests compared.Tests done on all tubers from 18 plants currently infected with PVS showed that 103 of 116 (89%) were infected, and virtually all eyes from 68 infected tubers produced infected plants.Three years of field trials at Fredericton on the spread of PVS showed that the virus moved into virus-free varieties independently of potato virus X (PVX). In 1970, leaf tests showed that virus-free Netted Gems became 12% infected with PVS; in 1971, spread into Green Mountain, Kennebec, and Sebago was 57, 19, and 9%, respectively; and in 1972, 14% spread occurred in Green Mountain and none in Kennebec or Sebago.Greenhouse experiments on transmission of PVS to potato by Myzus persicae (Sulz.) resulted in 3 of 87 (3.4%) plants becoming infected. Other tests with potato virus Y (PVY) to tobacco, Nicotiana tabacum L. var. Samsun, resulted in 83% transmission.
Necrotic And Common Strains Of Potato Virus Y And Resistance Of Plants Nicotiana Tabacum L. And Nicotiana Rustica L.
