Taxonomic information	Current valid scientific name: Meloidogyne fallax Synonyms: Meloidogyne chitwoodi (Baexem) B‐type Name used in the EU legislation: Meloidogyne fallax Karssen [MELGFA] Order: Rhabditida Family: Meloidogynidae Common name: false Columbia root‐knot nematode, root gall nematode Name used in the Dossier: Meloidogyne fallax
Group	Nematodes
EPPO code	MELGMA
Regulated status	The pest is listed in Annex II of Regulation (EU) 2019/2072 as Meloidogyne fallax Karssen [MELGFA]. The pest is included in the EPPO A2 list (EPPO, online_a). Meloidogyne fallax is quarantine in Morocco, Moldova and Norway. It is on A1 list of Argentina, Bahrain, Brazil, Egypt, Georgia, Kazakhstan, Russia, Ukraine and EAEU (=Eurasian Economic Union – Armenia, Belarus, Kazakhstan, Kyrgyzstan and Russia). It is on A2 list of COSAVE (=Comite de Sanidad Vegetal del Cono Sur – Argentina, Brazil, Chile, Paraguay, Peru and Uruguay) (EPPO, online_b). M. fallax is also quarantine pest in the US (Kantor et al., 2022). In the UK, M. fallax is regulated non‐quarantine pest in Great Britain on potato only, as this is considered to be the main host at risk (DEFRA, online; EPPO, online_b), and it is regulated quarantine pest in Northern Ireland (DEFRA, online; Dossier Section 5.0).
Pest status in the UK	Meloidogyne fallax is present in the UK (CABI, online; EPPO, online_c) with a restricted distribution in England and Wales and no findings associated with trees (Dossier Sections 2.0, 3.0 and 5.0). M. fallax was also detected in Northern Ireland in 2011 (EPPO, 2015); however, its presence there is currently not confirmed (Dossier Section 5.0).
Pest status in the EU	Meloidogyne fallax is present in Belgium, France, the Netherlands and Sweden; in the latter country, it is under eradication (DEFRA, online; EPPO, online_c,d). It is transient and under eradication in Germany (CABI, online; EPPO, online_c). M. fallax was present in Ireland in the past century (1965) (Topalović et al., 2017), but it has not been reported since.
Host status on Acer	Acer palmatum is reported as a host plant for Meloidogyne fallax in field experiments (den Nijs et al., 2004). There is no information on whether Acer platanoides may be a host for M. fallax. However given the polyphagous nature of M. fallax the PLH Panel cannot exclude that A. platanoides could be a hostplant for the nematode.
PRA information	Available Pest Risk Assessments: – Pest risk assessment for the European Community plant health: a comparative approach with case studies. Cases: Meloidogyne chitwoodi and M. fallax. (MacLeod et al., 2012); – Scientific Opinion on the commodity risk assessment of Acer spp. plants from New Zealand (EFSA PLH Panel, 2020); – UK Risk Register Details for Meloidogyne fallax (DEFRA, online).
Other relevant information for the assessment
Biology	Meloidogyne fallax is a highly polyphagous root‐gall nematode firstly described from the Netherlands and mostly distributed in temperate regions of the world. It is present in Africa (South Africa), Asia (Indonesia), Europe (Belgium, France, Germany, the Netherlands, Switzerland, Sweden, the UK), Oceania (Australia, New Zealand), South America (Chile) (CABI, online; EPPO, online_c). According to MacLeod et al. (2012) M. fallax may be more widespread because it is frequently confused with similar species as M. hapla and M. chitwoodi, and not causing clear external symptoms on host plants. Meloidogyne fallax has three development stages: eggs, juveniles (four stages) and adults. The nematode mainly reproduces parthenogenetically, and sexual reproduction can possibly occur under adverse conditions; like other Meloidogyne species, M. fallax has 1–3 generations per year depending on temperature and host availability (MacLeod et al., 2012; EFSA, 2019). Females lay up to 800–1,000 eggs in gelatinous masses on the root surface, in galls and tubers. Hatching can occur at temperatures below 10°C, so that M. fallax is considered cryophilic (MacLeod et al., 2012; EFSA PLH Panel, 2020). The second‐stage juveniles move in the soil and penetrate host roots, start feeding on cortical tissues inducing the formation of root galls; they become sedentary and develop to successive stages by quick moults. The nematode can stay infective in the soil for long time, being also able to survive for more than 300 days at temperatures of 5 and 10°C, and 140 days at higher temperatures (15–25°C). Survival and infectivity may be also related to high soil humidity (100% survival with 98% RH) although in moderate dry soil conditions, M. fallax may survive for more than 9 weeks (MacLeod et al., 2012). As other nematode species living in the soil, Meloidogyne fallax has only little spread capacity, the juvenile stages moving 1–2 m maximum per year depending on type of soil, water availability and other parameters (EFSA, 2019). Water could also disperse the nematode (mainly eggs and juveniles) at short distances. The human‐assisted spread on medium‐long distance is very frequent and effective by passive transport. Possible pathways are mainly plants for planting with infected roots; tubers and bulbs; soil and growing media; contaminated tools, machinery, shoes and packaging material (EFSA 2019).
Symptoms	Main type of symptoms	Meloidogyne fallax is a root‐knot nematode. Heavily infested plants show stunting and yellowing on above ground parts and galling on roots (Moens et al., 2009; MacLeod et al., 2012; EFSA, 2019). Symptoms of root‐knot nematodes on hardwood trees may show as slow growth, sparse foliage, chlorotic leaves and crown dieback (Riffle, 1963). Symptoms on roots vary with species but should be visible as galls in advanced infections. On potato tubers, M. fallax cause numerous small pimple‐like areas on the surface (EPPO, 2019). No specific information about symptoms on Acer sp. was found.
	Presence of asymptomatic plants	At the early stages of infection, plants may not show any apparent symptoms on the above ground parts and do not show galls on the roots. In some cases, plants are wilted and lack vigour. The main impact of the pest is on root growth, and on the quality and growth of the plant (Moens et al., 2009; MacLeod et al., 2012; EFSA, 2019).
	Confusion with other pests	Meloidogyne fallax is morphologically very similar to M. chitwoodi and may also be easily confused with other species as M. hapla and M. minor, often found in the same habitat. M. fallax cannot be identified on the basis of sole galls, since other soil nematode cause similar damage and some insects and bacteria can induce comparable galls on roots as well (EFSA, 2019). The nematode can be identified by laboratory tests on morphometric characters, electrophoresis or sequencing/DNA barcoding are needed (EPPO, 2016).
Host plant range	Meloidogyne fallax is a polyphagous nematode with a wide host range, including several major horticultural and agricultural crops and a few species of trees, shrubs and herbaceous plants. Main horticultural/agricultural hosts are Apium graveolens, Allium porrum, Asparagus officinalis, Avena strigosa, Beta vulgaris, Cicorium endivia, Cynara scolymus, Daucus carota, Foeniculum vulgare, Fragaria ananassa, Hordeum vulgare, Lactuca sativa, Lycopersicum esculentum, Medicago sativa, Phaseolus vulgaris, Secale cereale, Solanum nigrum, S. tuberosum, Solanum spp., Triticum aestivum and Zea mays (MacLeod et al., 2012; CABI, online; EPPO, online_e). Woody hosts of M. fallax are Acer palmatum, Betula pendula, Cornus sanguinea, Laburnum anagyroides, Lonicera xylosteum (MacLeod et al., 2012; Ferris, online). For a more exhaustive list of hosts, see de Nijs et al. (2004); MacLeod et al. (2012); CABI (online); EPPO (online_e) and Ferris (online)
Reported evidence of impact	Meloidogyne fallax is EU quarantine pest. Meloidogyne fallax is known as species of economic concern on some horticultural crops as potato and carrot, mostly in the Netherlands, but no information is available on yield losses. The main damage observed is the reduction of merchantability in potato tubers (MacLeod et al., 2012). Similarly, no significant damage was observed on strawberries (van der Sommen et al., 2005). Few reports demonstrate the impact of M. fallax on yield or quality of plant products. The nematode species has been reported to be of economic importance on potato and carrot in the Netherlands, but no data were given on yield losses in practice (MacLeod et al., 2012). Damage caused by M. fallax in sports turf were reported in North‐western England in 2015 (EPPO, 2015; DEFRA, 2017). No specific data about damage on Acer sp. was found.
Evidence that the commodity is a pathway	Meloidogyne nematodes, although rarely identified at species level, are frequently intercepted on plants for planting, including bonsais of Acer palmatum (EUROPHYT/TRACES, online); therefore, the commodity is a possible pathway of entry for M. fallax.
Surveillance information	According to the Dossier Section 3.0 and 5.0, Meloidogyne fallax is not under official surveillance, as does not meet criteria of quarantine pest for Great Britain.