A SURVEY OF TYLCD EPIDEMICS IN SARDINIA (ITALY) – ESTIMATING THE ENVIRONMENTAL INOCULUM AND CORRELATING IT WITH WHITEFLY POPULATION TRENDS

Since its introduction during the late 1980s, tomato yellow leaf curl disease (TYLCD) has become one of the most serious threats of greenhouse tomatoes in the south of Sardinia (Italy). To gain information about the epidemiology of the disease, we monitored for four years the seasonal variations in viral inoculum and the dynamics of vector populations outside greenhouses, in one of the main tomato production areas of the island.
Our results indicate that in this district the risk of disease transmission to tomato crops is high for at least five months, from May to September.
Both the spread of the disease and the trends of whitefly population, consisting mainly of the greenhouse whitefly Trialeurodes vaporariorum, generally showed a major peak in June, with an environmental inoculum capable in most cases of infecting 80-100% of tomato bait plants.
During summer, when the vector of the disease Bemisia tabaci became prevalent, the patterns of TYLCD incidence and whitefly population diverged, with the former remaining high and the latter decreasing to lower levels.
By early autumn the incidence of virus infection finally dropped drastically.
These results confirm the reports of field observations, which indicate greenhouse tomatoes grown in summer as the most exposed to TYLCD.

III International Symposium on Tomato Diseases

M. Nannini, F. Foddi, G. Murgia, R. Pisci, F. Sanna , M. Testa, G.P. Accotto

geminiviruses, Bemisia tabaci, Trialeurodes vaporariorum, tomato

https://doi.org/10.17660/ActaHortic.2011.914.32