Evaluation continues

Candidate

The host range of B. tabaci covers more than 1 000 species (Mound and Halsey, 1978; De Barro, 1995; Chu et al., 2006; Evans, 2007; Li et al. 2011; EFSA, 2013). Euphorbia pulcherrima and Euphorbia sp are listed as the main ornamental host plants of B. tabaci (Mound and Halsey, 1978; De Barro, 1995; Chu et al., 2006; Dalton, 2006; Evans, 2007; DAF-GWA; 2008; Dalmon et al. 2008; Drayton et al., 2009; Li et al., 2011; EFSA, 2013). In 1987-1993, Fransen (1994) reported an average of 10 annual findings of B. tabaci on Euphorbia pulcherrima in the greenhouses in the Netherlands. The infestation rate (nymphs and pupae density) of host plants of B. tabaci was categorized in four grades in China (Li et al., 2011). Euphorbia pulcherrima was classified with the highest infestation rate – 4th grade (average number of B. tabaci nymphs and pupae > 50/10 cm² leaf area) (Li et al., 2011). Ornamental trade, particularly the poinsettia pathway, was proposed as the main pathway of introduction (and spread) of B. tabaci MEAM1 and Med in the United States (Dalton, 2006), China (Chu et al., 2006), New Zealand (Drayton et al., 2009) and Brazil (Moraes et al., 2017). For the period 1993–2011, 189 interceptions (16% of all interceptions) of B. tabaci are registrated on Euphorbia plants for planting originating from third countries. 325 interceptions on plants for planting from the EU are reported on Euphorbia spp. (61% of all interceptions). Most of interceptions in the EU originating from the Netherlands (46 %) and Germany (17 %) (EUROPHYT; EFSA, 2013). Euphorbia pulcherrima and Hibiscus are the main host plants infested with B. tabaci in the greenhouses in Bulgaria (EPPO Global Database, 2012; EFSA, 2013).
Except in the Mediterranean coastal region (Cyprus, Greece, Malta, Italy, south of France, certain parts of Spain and Portugal), B. tabaci occurrence is restricted in the EU to greenhouses. Growing B. tabaci host plants under exclusion conditions may be highly effective in the management of this pest and its associated viruses in both field and greenhouse-grown crops, however detailed attention must be given to exclusion netting and entrances etc. For crops in fields or partly-covered facilities, in areas where the pest is established (the Mediterranean coastal region), infestation can take place by flying adults, up to a maximum of 7km in a 12-hour period, though this is not a limiting factor because, with the wide range of putative hosts, suitable host plants are mostly available, and under intensive production suitable host plants, densely spaced, are found within a short distance. Under protected cultivation, plant production is throughout the year and suitable crops follow and rotate at tight intervals, favouring the establishment and dispersal of B. tabaci. Whitefly adults can migrate over long distances via passive transport with wind. However, even considering a climate change scenario with an increase of on average + 2 °C, B. tabaci distribution will expand its most Northern limit but still will not establish outdoors in Northern EU Member States (EFSA, 2013). Experts concluded that the level of importance of the pathway depends very much on conditions e,g, areas of concentrated glasshouse production versus areas where protected cultivation units are isolated from one another (as for Dendranthema) but evidence of plants as pathway is much stronger for this host.
In conclusion, it is suggested plants for planting would be a significant pathway for crops grown in protected facilities in most of the countries where the pest is not present outside in the environment.
For Mediterranean coastal region (Cyprus, Greece, Malta, Italy, south of France, certain parts of Spain and Portugal, for field and protected crops, plants for planting would not be a significance source because of the natural dispersal of the pest by flight/wind and the likely ability to eventually enter protected facilities.

Yes

B. tabaci is considered to be one of the most serious threats to crop cultivation worldwide, predominantly because of the large number of viruses it transmits. It is a sap-sucking insect that can reduce the vigour of plants and excrete a sticky, sugary substance, called honeydew, on the leaves, stems and fruits of its host plants. Adults can also transmit important virus diseases to major vegetable crops, but ornamental species, with only a few exceptions (e.g. Eustoma sp., Lisianthus sp., Manihot sp.), are not considered host plants for viruses transmitted by B. tabaci. Euphorbia pulcherrima is therefore not affected by B. tabaci transmitted viruses but circulatively transmitted viruses (begomoviruses) can also be carried by viruliferous B. tabaci insects along non-hosts plants (EFSA, 2013).

Yes

Yes

Candidate

Viruliferous B. tabaci insects may not pose an unacceptable risk to the ornamentals but can transfer viruses to vegetable crops sometimes grown in the same premises. Ornamentals may therefore pose an unacceptable risk to plants in the vegetable sector. Appropriate protection measures need to be in place to limit yield losses, and this also includes crops not affected by viruses transmitted by B. tabaci (ornamentals) but on which insect populations can develop rapidly (EFSA, 2013).

candidate