Scaphoideus titanus Ball is a nearctic leafhopper that was introduced for the first time in Europe in 1950’s. In Europe this species is monophagous for the grapevine and is of great economic importance as the vector of Flavescence dorée, a grapevine yellow disease caused by phytoplasmas of the 16Sr-V group. In the present study, the Random Amplified Polymorphic DNA (RAPD) techinque was employed to obtain the first genetic information about the diffusion and the structure of S. titanus populations. Two American populations and fourteen European populations were analysed. One hundred and eighty-eight reproducible bands, obtained from three twentymer arbitrary primers, were considered to assess the amount and the pattern of genetic variation within and among leafhopper populations. American populations showed the highest degree of genetic variabity and appeared to be the most isolated of all the tested samples. The results confirm the historical role of American samples as the sources for the more recently founded European populations. RAPD analyses revealed a weak genetic structure of European samples that could probably be explained invoking the human role in their diffusion. The non-natural spreading of S. titanus across Europe is in fact attributable to the exchange of grapevine hybrids carrying eggs that the insect laid under the bark to overwinter. This indicates the real importance of rigorous quality controls on the plant to be exchanged, not only for the presence of phytoplasma infections but also for the presence of leafhopper eggs.
Spreading of the neartic leafhopper Scaphoideus titanus Ball in Europe as a consequence of human trade.
BERTIN, SABRINA;
2006-01-01
Abstract
Scaphoideus titanus Ball is a nearctic leafhopper that was introduced for the first time in Europe in 1950’s. In Europe this species is monophagous for the grapevine and is of great economic importance as the vector of Flavescence dorée, a grapevine yellow disease caused by phytoplasmas of the 16Sr-V group. In the present study, the Random Amplified Polymorphic DNA (RAPD) techinque was employed to obtain the first genetic information about the diffusion and the structure of S. titanus populations. Two American populations and fourteen European populations were analysed. One hundred and eighty-eight reproducible bands, obtained from three twentymer arbitrary primers, were considered to assess the amount and the pattern of genetic variation within and among leafhopper populations. American populations showed the highest degree of genetic variabity and appeared to be the most isolated of all the tested samples. The results confirm the historical role of American samples as the sources for the more recently founded European populations. RAPD analyses revealed a weak genetic structure of European samples that could probably be explained invoking the human role in their diffusion. The non-natural spreading of S. titanus across Europe is in fact attributable to the exchange of grapevine hybrids carrying eggs that the insect laid under the bark to overwinter. This indicates the real importance of rigorous quality controls on the plant to be exchanged, not only for the presence of phytoplasma infections but also for the presence of leafhopper eggs.
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