Studies on the epidemiology of tomato yellow leaf curl begomovirus in Spain
Tomato yellow leaf curl begomovirus (TYLCV - EPPO A2 quarantine pest) was first reported in Spain in 1992 (EPPO RS 93/026). Since then, it has spread to the main vegetable-producing regions of southern and south-eastern Spain where it is a limiting factor for tomato production during summer and autumn (up to 100 % losses can be reached). So far, TYLCV-Sr isolates were involved in outbreaks, but more recently in the same regions, abnormally severe outbreaks are observed and are associated with TYLCV-Is. Studies have been carried out on the possible factors responsible for this displacement: competition between TYLCV-Sr and TYLCV-Is in tomato plants, transmission by local biotypes (B and Q) of Bemisia tabaci, and presence in weeds or other crops. Results showed that there is apparently no competition between TYLCV-Sr and TYLCV-Is in tomato plants. TYLCV-Is is more efficiently transmitted by the local biotypes of B. tabaci than TYLCV-Sr. Concerning weeds, both types of isolates are rarely found in wild plants growing around tomato fields. But Datura stramonium and Solanum nigrum may be possible reservoirs for the virus. More significantly, it was found that bean (Phaseolus vulgaris) is a host plant of TYLCV-Is but not of TYLCV-Sr. Bean is often cultivated between tomato crops and can act as a reservoir for the virus. The authors concluded that the cultivation of bean which can host TYLCV-Is between tomato crops and the efficiency of local biotypes of B. tabaci to transmit TYLCV-Is are probably two factors responsible for the displacement of TYLCV-Sr by TYLCV-Is in Spain.
Sánchez-Campos, S.; Navas-Castillo, J.; Camero, R.; Soria, C.; Díaz, J.A.; Moriones (1999) Displacement of tomato yellow leaf curl virus (TYLCV)-Sr by TYLCV-Is in tomato epidemics in Spain.
Phytopathology, 89(11), 1038-1043.