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Disease Detection and Losses

Infectivity of Potato Spindle Tuber Viroid in Potato Plant Parts. R. P. Singh, Research Scientist, Research Station, Research Branch, Agriculture Canada, Fredericton, New Brunswick, Canada E3B 4Z7; Phytopathology 67:15-17. Accepted for publication 4 August 1976. Copyright © 1977 The American Phytopathological Society, 3340 Pilot Knob Road, St. Paul, MN 55121. All rights reserved.. DOI: 10.1094/Phyto-67-15.

The infectivity of potato spindle tuber viroid (PSTV) was followed at weekly intervals up to 14 weeks after inoculation into potato (Solanum tuberosum ‘Netted Gem’). The viroid was assayed on Scopolia sinensis leaves from extracts of roots, lower and upper stems, and middle and apical leaves of potato plants. The PSTV was detected from the middle leaves and roots as early as 1 week after inoculation, although infectivity was very low. The highest infectivity in most plant parts was reached 4-8 weeks after inoculation and then declined sharply. The infectivity was highest in extracts from the mature leaves in the middle of the plant and lowest in roots and tuber extracts.