Scientific Opinion on the pest categorisation of Candidatus Phytoplasma solani

Abstract

The Panel on Plant Health performed a pest categorisation of potato stolbur mycoplasma, recently renamed Candidatus Phytoplasma solani (CPs), for the European Union (EU) territory. CPs is a well-defined species of the genus Candidatus Phytoplasma, for which molecular detection assays are available. It is a regulated harmful organism in the EU, and is listed as potato stolbur mycoplasma in Annex II, Part A, Section II of Council Directive 2000/29/EC. Although CPs can infect a wide range of host plants, this listing concerns only Solanaceae plants for planting. CPs is transmitted by grafting and vegetative propagation of infected hosts, and by several insect vector species including Hyalesthes obsoletus, Reptalus panzeri, Pentastiridius leporinus and possibly others. The geographical distributions and population densities of these vectors govern the spread of CPs. CPs can infect a wide range of host plants and has been reported in 14 EU Member States (MSs). CPs can cause yield losses in potato and other solanaceous crops, in grapevine, strawberry, maize and lavender. Because host plants, wild or cultivated, are widely distributed throughout the EU, the distribution of vector populations is the main determinant of CPs establishment and spread; therefore, CPs has the potential to establish and spread in unaffected parts of the EU with the extension of the distribution range of its vectors. There are high annual fluctuations in the impact of CPs, and this is mostly affected by the prevalence of plant reservoirs for CPs and by the size of local vector populations, which cannot easily be controlled. There are uncertainties regarding the precise distribution of CPs and its vectors, the evolution of vector distribution, the long-term impact of emerging CPs genotypes and the extent of impact on the various susceptible crops grown in the EU.

Epidemiological Investigations and Molecular Characterization of ‘Candidatus Phytoplasma solani’ in Grapevines, Weeds, Vectors and Putative Vectors in Western Sicily (Southern Italy)

“…These results coincide with other studies that highlighted a different sensibility to BN according to the cultivar. 'Chardonnay', 'Riesling', 'Cabernet Sauvignon', 'Barbera', 'Sauvignon blanc', and 'Sémillon' are among the most sensitive cultivars [32,33], while some local varieties of Caucasus region (Georgia) as well as Vitis simpsonii, showed low susceptibility [21,34]. On 'Chardonnay' infected by BN, important changes have been reported for gene expression [35], for physiological parameters [36], and for fruit yield and wine quality [37].…”