Studies on Potato yellow vein crinivirus in South America
It is recalled that sporadic outbreaks of potato yellow vein disease (EPPO A1 quarantine pest) were first observed by potato growers in Antioquia, Colombia, as early as 1943. Disease incidence rapidly reached alarming levels, and yield losses were observed as affected plants usually produce fewer tubers. It was noted that Trialeurodes vaporiorum transmitted the disease. Recent studies done in South America showed that the disease is associated with a crinivirus called Potato yellow vein crinivirus. Epidemiological surveys carried out in Rio Negro, Colombia showed that weeds such as Polygonum mepalense could provide important reservoirs for Potato yellow vein crinivirus. Lower virus concentrations were also found in Rumex obtusifolium, Tagetes and Catharanthus roseus. Further details were given on its geographical distribution in South America.
- Colombia: during 1995-1998, visual surveys showed that disease incidence varied among potato fields. It varied from 5 to 80 % in Rionegro (1997), and from 10 to 60 % in Cundinamarca (1995-1998). In Boyaca, no symptoms were seen (1996).
- Ecuador: the disease has been observed in Ibarra and Quito (it was found there even before 1996).
- Peru*1: in 1996, the disease was observed in 2 fields in Chota (Cajamarca), 3 fields in Huaras, and 1 field in Huancayo. In Cajamarca and Huaras, disease incidence varied from 5 to 98 %, whereas in Huancayo, only 2 potato plants showed symptoms. Information gathered from farmers and extension services suggested that the disease has been recently introduced, probably from Ecuador or Colombia.
- Venezuela: in 1998, diseased plants were observed in 4 states: Lara, Merida, Tachira and Trujillo. Incidence in potato fields above 1700 m was 3-10 %. Affected cultivars were mostly of Colombian origin.
The authors concluded that considering its transmission via trade of seed potatoes, the increase of T. vaporariorum populations and its survival in weeds, Potato yellow vein crinivirus represents a potential threat to the world potato production.
* The EPPO Secretariat had previously no data on the occurrence of this virus in Peru.
Sources
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Salazar, L.F.; Müller, G.; Querci, M.; Zapata, J.L.; Owens, R.A. (2000) Potato yellow vein virus: its host range, distribution in South America and identification as a crinivirus transmitted by Trialeurodes vaporariorum.
Annals of Applied Biology, 137(1), 7-19.
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