Table 1.

Examples of plant viruses that have emerged in crops grown in non-native environments

Virus	Geographical emergence	Date first reported	Origin of crop plant	Source of virus	Reference
Cassava mosaic geminiviruses	East Africa	1894	South America	Unknown	[70•]
Cacao swollen shoot virus	West Africa	1900	Central America	Local trees from the Malvaceae	[80]
Maize streak virus	Africa	1928	Central America	Wild native grasses	[81]
Tomato yellow leaf curl virus	Israel	1930	South America	Infects many wild hosts, origin not clear	[82]
Sugarcane yellow leaf virus	Southern United States, Central and South America	1994	Southern Asia	Host unknown, but originated in Columbia	[83]
Pepino mosaic virus	Peru, but has emerged in tomato around the world	1980	South America	Wild native Solanum species	[73]
Tomato torroado virus	Spain	1996	South America	Unknown, infects many Solanaceae	[84]
Iris yellow spot virus	Brazil	1981	Worldwide	Unknown, but common in weeds	[85]
Plum pox virus	United Statesa	1999	China	Unknown, may have arrived from Europe on nursery stock	[86]
Wheat mosaic virusb	United States	1993	Turkey	Unknown but also found in maize (a native crop)	[87]

^aWidespread in Europe, emerged in eastern US recently.

^bAlso called High plains virus.