Prevalence of potato yellow vein virus (PYVV) in Solanum tuberosum Group Phureja Fields in Three States of Colombia

Potato yellow vein virus (Crinivirus) causes leaf yellowing, is limited to the phloem and is transmitted by Trialeurodes vaporariorum and tubers. PYVV causes up to 50 % yield reduction in S. tuberosum. The prevalence of PYVV was established in Group Phureja in 2008 in the Colombian states of Cundinamarca, Antioquia and Nariño. The presence (S) or absence (NS) of symptoms was established in 24,930 plants. Symptom prevalence was as follows: Cundinamarca 0.74 % ± 0.03, Antioquia 5.4 % ± 12 and Nariño 6.2 % ± 0.11. Percentages of S plants were highly variable among different states and municipalities. PYVV was diagnosed by RT-PCR in a subsample of 1,545 plants from Cundinamarca and Nariño. RT-PCR showed that 2.4 % ± 8.3 × 10−5 and 41 % ± 0.0009 % of the symptomless plants of Cundinamarca and Nariño respectively were positive. This suggests possible late infection of plants by the vector which did not have enough time to express symptoms, infections with two or more viruses or “virus latency”. PYVV symptomatic prevalence in Group Phureja was lower than that reported for Diacol-Capiro (Group Andigena), but increases if molecular results are taken into account. This is the first known study aimed at determining PYVV prevalence using molecular tools and extensively sampling of S.tuberosum Group Phureja plants in grower’s fields in three states and multiple municipalities of Colombia.