Epidemiology of tomato spotted wilt tospovirus in tomato fields
At present in Spain, tomato spotted wilt tospovirus (EPPO A2 quarantine pest) is a limiting factor to the production of many vegetable crops, and severe economic losses have been observed in important crops such as tomato, pepper or lettuce. The epidemic outbreaks of tomato spotted wilt tospovirus have been related to the introduction and spread of Frankliniella occidentalis (EPPO A2 quarantine pest). A survey was carried out in commercial tomato fields in northeastern Spain (near Barcelona) during two growing seasons (1993-94), to study the incidence of tomato spotted wilt, the densities of F. occidentalis populations, and the relative number of viruliferous thrips. Results showed that early thrips abundance could be related with final disease incidence for early transplanted tomato crops. The situation was totally different for late transplanted tomatoes. In this case, low adult numbers were detected throughout the season, whereas disease incidences were comparable to those found in early transplanted tomatoes. For late transplanted tomatoes, it was also observed that significantly more viruliferous thrips were present in the initial growth phases compared with early transplanted crops. The sources for these highly viruliferous populations were probably nearby crops like early transplanted tomatoes, where an increase in the infectious potential of thrips populations was detected during the same period. The authors noted that the initial phase of the crop (0-60 days after transplanting) is the critical one for the development of the disease, and this fact should be taken into account when developing control strategies against tomato spotted wilt tospovirus.
Sources
Aramburu, J.; Riudavets, J.; Arnó, J.; Laviña,, A.; Moriones, E. (1997) The proportion of viruliferous individuals in field populations of Frankliniella occidentalis: implications for tomato spotted wilt virus epidemics in tomato.
European Journal of Plant Pathology, 103(7), 623-629.