The incidence of viruses in Serbian potato seed production

Potato (Solanum tuberosum subsp. tuberosum) is very important field crop grown in Serbia. A significant number of pathogens, including viruses, can naturally infect potato crops. Virus infections have been associated with potato degeneration and declining productivity of seed stock in the major potato producing countries. Domestic production of potatoes is mainly based on seeds of the class “certified” imported from northern European countries. In this study we examined the annual increase in viral infection in domestic production of seed potatoes in two consecutive years. A survey to determine the incidence of potato virus diseases was carried out in four major potato growing areas in Serbia. Tubers were harvested from 591 field crops in 25 locations during September 2012 and from 507 field crops in 23 locations during August 2013. Disease incidence was confirmed by the laboratory testing using double antibody sandwich (DAS)ELISA test on Potato virus Y (PVY), Potato virus A (PVA) (monoclonal antibody), Potato leaf roll virus (PLRV), Potato virus S (PVS), Potato virus X (PVX) and Potato virus M (PVM) (polyclonal antibody) of Bioreba production. Infection were detected in 477 out of 591 (80.71%) and in 312 out of 507 (61.54%) crops in 2012 and 2013, respectively. In 2012, out of 14775 samples tested by ELISA, 5819 samples were infected by PVY, 184 by PLRV and only one by PVS. Mixed infection PLRV+PVY was detected in 149 samples (1,01%). In 2013, 2654 samples were infected by PVY from 12675 tested samples, and 95 by PLRV. Mixed infection with PLRV+PVY was present in 37 samples (0.25%). Results of laboratory testing showed the occurrence of at least two viruses, with PVY being the most widely distributed, 39.62% and 21.39% of tested samples in 2012 and 2013 respectively. Other viruses identified were less present. In 2012, PLRV was detected in 1.24%. In 2013, 0.75% samples were infected with PLRV, while PVS was detected only sporadically. PVA, PVX and PVM were not detected in any of the samples tested in the years of investigation. PVY was the most frequently detected virus, detected in 39% and 21% of samples collected in 2012 and 2013, respectively. PVY proved to be endemic throughout Serbia.