Evaluation continues

Candidate

Candidatus Phytoplasma solani' (CPs) is transmitted by grafting and vegetative propagation of infected hosts, and by several insect vector species (EU COM, 2016). With the exception of lavender and maize, most crops affected by CPs are dead-end hosts as they are not hosts for the insect vectors. However, weed species can act as a reservoir (EFSA-PLH, 2014). In Germany the organism was for example found in potatoes in two consecutive years in the same area and the suspected source was infected weeds in the surroundings (EPPO Reporting Service 2008/213; 2010/155). As a consequence, natural spread from the reservoir of infected weed species is the main pathway of spread to actively growing crops in areas where the organism is present. CPs is not thought to be transmitted in the true seed of any of its hosts (EPPO, Data Sheets on Quarantine Pest), so vegetable propagating and planting material can only become a pathway in the limited timeframe between sowing and transplantation of the propagating and planting material. Regarding vegetable Solanaceae, it has been found in tomato, pepper, and aubergine (EFSA-PLH, 2014). Most young plants of vegetable Solanaceae are usually grown in protected conditions where the vector is absent and weeds can be controlled. Given that the major agricultural Solanaceous crops are dead-end-hosts, the only potential economic impact arises from the negative effects of CPs on the infected transplants themselves. Furthermore, it is not clear whether vectors spread CPs within economic host crops to any extent. In fact, in nature, the economically important host crops are not important for the continuity of the virus; an incomparably greater role is played by such wild plants as Convolvulus arvensis , clovers and, probably, Asteraceae and other plants (EPPO, Data Sheets on Quarantine Pest).
The vegetable SEWG concluded that plant for planting is only a significant pathway in relation to plants grown under protected conditions, when the vector can be excluded.

Yes

Severe impact of CP on plant growth, fruit yield and quality is recorded for infected tomato, eggplant and pepper plants (Fialova et al., 2009; Navràtil et al., 2009; Marchoux and Rougier, 1987). In severe epidemics, yield losses as high as 60 % in tomato and 93 % in pepper have been reported (EFSA-PLH, 2014).

Medium

No

Candidate

Impact is considerate moderate to minor, fluctuating and depending on climate, presence of weed inoculum sources and vector populations. Impact is strongly affected by natural spread (EFSA-PLH, 2014).

candidate

Yes, for plants grown under protective conditions: For young plants raised under protected conditions, it may be possible to keep the plants free of the pest. For any plants grown outside, there will be no practical measures to prevent infections by vectors, which are both very good fliers and difficult to tackle by insecticide suppression. Young plants of fruit vegetables that are grown under protected conditions (tomato, pepper, eggplant) are usually grown in glasshouses that have insect screens in the windows (situation in the Netherlands), but not during the part of the season (hot dry summers) which stimulate vector migration. Measures to avoid unacceptable economic impact on vegetable propagating and planting material therefore seem somewhat redundant.