Tomato chlorosis virus (ToCV) and Tomato infectious chlorosis virus (TICV) are whitefly-transmitted criniviruses in the family Closteroviridae. Both viruses can have serious, yield-reducing effects upon tomato production if suitable control is not administered. Recent outbreaks in other countries have caused extensive economic damage to the production of tomatoes.
Both viruses were discovered in the USA as recently as the 1990s. TICV was first detected in the Irvine region of Orange County, California in 1993. ToCV was first detected in Florida in 1998. The viruses have since spread worldwide into all major tomato-growing areas. Before the discovery of these viruses as causal agents of viral leaf yellowing (chlorosis), the symptoms they induced on tomatoes were often attributed to nutritional and physiological disorders or pesticide phytotoxicity, as they appear very similar. As viruses that are known to be present but distributed locally within the region covered by the European and Mediterranean Plant Protection Organisation (EPPO), they are included on the EPPO A2 list and it is recommended that they are regulated as quarantine pests in the EPPO region.
Both viruses are spread by the greenhouse whitefly (Trialeurodes vaporariorum), but ToCV may also be transmitted by other whitefly species including several biotypes of Bemisia tabaci. Although both viruses are considered to have only tomato as their major economic host, they can infect a broader range of plant species including a range of common weeds.
In 2017, ToCV was detected in the Netherlands for the very first time in glasshouses of three fruit-production companies. The status of this outbreak is currently ‘transient – under eradication’.