Occurrence, Prevalence and Distribution of Citrus Viroids in Uruguay

Abstract

The occurrence of Citrus exocortis viroid (CEVd), Citrus bent leaf viroid (CBLVd), Hop stunt viroid (HSVd), Citrus dwarfing viroid (CDVd), Citrus bark cracking viroid (CBCVd) and Citrus viroid VI (CVd-VI) in Citrus spp. cultivated in six provinces of Uruguay was surveyed in 20082009 and 2009-2010 growing seasons using Northern blot hybridization. Sixty two per cent of surveyed trees were infected with either single or mixed viroid inocula, the latter being more abundant. CBCVd and CVd-VI were not detected in the samples analyzed. HSVd showed the highest prevalence (92%) among infected plants followed by CDVd (50%), CEVd (23%) and CBLVd (19%). The most frequently observed viroid combination was HSVd+CDVd. Our results showed that CEVd, CBLVd, HSVd, CDVd are widespread throughout citrus orchards in Uruguay and highlight the presence of mixed viroid infections.