Various research bodies in Italy, the Universities of Palermo and Catania, IPSP-CNR Portici, CREA Rome and OMP Palermo conducted a study on the incidence and genetic diversity of the New Delhi virus.
The New Delhi virus (Tomato leaf curl New Delhi virus, ToLCNDV) is a bipartite begomovirus (family Geminiviridae) identified for the first time in 1995 in Asia, from where it spread into several countries in the Mediterranean basin. ToLCNDV was found in Spain in 2012 and subsequently in Tunisia and Italy.
In Italy, the first outbreak occurred at the end of 2015 in the Trapani province (Sicily) on zucchini. In 2016, infected zucchini plants were found in Campania, Lazio and Sardinia and in 2017 they were found in Calabria.
"The study addressed the dispersion and genetic diversity of ToLCNDV isolates in Italy. 1400 plants were analyzed in total. The phylogenetic analysis showed a low variability among Italian isolates, probably due to the recent introduction and rapid spreading of the virus in Italy."
"Two statistically significant clusters were reported: one grouping only Italian isolates and the other grouping Italian, Spanish, Tunisian and Moroccan isolates. Furthermore, the highest incidence of ToLCNDV was observed in Sicily although the disease appears critical also in other Italian regions."
This work proved a high efficiency of ToLCNDV mechanical transmission in Cucurbita pepo, Cucumis melo inodorus and Cucumis melo cantalupensis. "The rapid spreading of ToLCNDV in the Mediterranean basin represents a threat for horticultural production, so it is very important to develop suitable crop management practices applying genetic resistance strategies and more restrictive phytosanitary measures."
Source: S. Panno A. G. Caruso E. Troiano M. Luigi A. Manglli T. Vatrano G. Iacono S. Marchione S. Bertin L. Tomassoli G. Parrella S. Davino, 'Emergence of tomato leaf curl New Delhi virus in Italy: estimation of incidence and genetic diversity', 2019, Plant Pathology, Vol. 68 (3), pag. 601-608.