Figure 4.

Typical symptoms of viroid infection in various crops. In all cases, mock-inoculated or symptomless plants are on the left, and viroid-infected plants are in the center and/or on the right. (A) PSTVd induces potato tuber malformations (image modified from original credited to William M. Brown Jr., Bugwood.org, accessed on 16 January 2023). (B) Symptomless infections induced by ELVd in eggplant (cv. Black Beauty). (C) Peach calico-inducing variants of PLMVd induce severe chlorosis in peach leaves (left image adapted from https://doi.org/10.3389/fpls.2012.00288, accessed on 16 January 2023; right image modified from original credited to H.J. Larsen, Bugwood.org). (D) CSVd infection induces stunting and earlier blooming in chrysanthemum (top), resulting in flower breaking and deformation (bottom) (top image modified from original credited to J. Dunez, Bugwood.org, accessed on 16 January 2023; bottom image modified from original credited to European and Mediterranean Plant Protection Organization, Bugwood.org, accessed on 16 January 2023. (E) Co-inoculation of citrus trees with CBLVd and CDVd induces symptomless infections in trees (left), while co-inoculation of CEVd and CBCVd induces bark scaling characteristic of CEVd infection (center) or severe bark cracking characteristic of CBCVd infection (right). Parts of this figures have been adapted from [144,183,184,185].