The citrus gummy bark viroid (abbreviated CGBVd) is a strain of '' Hop stunt viroid'', and thus is a member of the genus ''

Hostuviroid Hostuviroid is a genus of ssRNA viroids that includes '' Hop stunt viroid'', a species of viroids that infects many different types of plants, including the common hop plant. It belongs to the family ''Pospiviroidae The Pospiviroidae are a '' ...

''. As the name suggests, the citrus gummy bark viroid causes problems in the bark of the

sweet orange The orange, also called sweet orange to distinguish it from the bitter orange (''Citrus × aurantium''), is the fruit of a tree in the family Rutaceae. Botanically, this is the hybrid ''Citrus'' × ''sinensis'', between the pomelo (''Citrus ...

tree. Scraping the bark exposes localized spots or a line of reddish-brown, gum-impregnated tissue around the

scion Scion may refer to: Horticulture *Scion (grafting), in horticulture, the upper part of a combined plant Arts, entertainment, and media Characters *Atlantean Scion, a device in the ''Tomb Raider'' video game series *Scion, avatar of the warrior en ...

circumference especially visible near the bud union. The discoloration and gumming may extend above the bud union to the main branches of the sweet orange while in severe infection dark streaks of gum-impregnated tissue may also be observed in longitudinal sections.

References

Viroids Viral citrus diseases Infraspecific virus taxa {{virus-stub