The genus Pospiviroid (family Pospiviroidae) contains ten recognized species: Chrysanthemum stunt viroid (CSVd), Citrus exocortis viroid (CEVd), Columnea latent viroid (CLVd), Iresine viroid 1 (IrVd-1), Mexican papita viroid (MPVd), Pepper chat fruit viroid (PCFVd), Potato spindle tuber viroid (PSTVd), Tomato apical stunt viroid (TASVd), Tomato chlorotic dwarf viroid (TCDVd), and Tomato planta macho viroid (TPMVd). Is a circular, ssRNA, consisting of 240-400 nucleotides.
Pospiviroids are responsible for economically important diseases of horticultural and agricultural crops, including tomato (Solanum lycopersicum), potato (Solanum tuberosum), pepper (Capsicum annuum), citrus (Citrus spp.) and ornamental chrysanthemum (Chrysanthemum morifolium). All pospiviroid species, except IrVd-1, are able to infect tomatoes and produce similar symptoms such as stunting, epinasty, leaf distortion, smaller fruit and reduced yield.