Taxonomic information	Current valid scientific name: Pratylenchus loosi Loof, 1960 Synonyms: – Name used in the EU legislation: not regulated in the EU Name used in the Dossier: Pratylenchus loosi Loof Order: Rhabditida Family: Pratylenchidae
Group	Nematoda
EPPO code	PRATLO
Regulated status	EU status: – Non‐EU: A1 list: Argentina (2019) (EPPO, Global Database)
Pest status in Turkey	Present, (CABI, online)
Pest status in the EU	Present in Bulgaria (CABI, online)
Host status on Malus domestica	In CABI Plantwise Knowledge Bank (online) apple, Malus domestica is recorded as a host of Pratylenchus loosi (https://www.plantwise.org/KnowledgeBank/datasheet/43898).
PRA information	There is no PRA available.
Other relevant information for the assessment
Biology	Pratylenchus loosi belongs to the group of root lesion nematodes, Pratylenchus spp., with over 60 named species. Root lesion nematodes are the third most important group of nematodes after root‐knot and cyst nematodes, which have significant economic impacts on crops worldwide (Castillo and Vovlas, 2007; Jones et al, 2013). Like other root lesion nematodes, P. loosi is polyphagous, migratory endoparasite that occurs in both soil and roots. Although root lesion nematodes are polyphagous, there are distinct differences in host preferences among species in this nematode group (Castillo and Vovlas, 2007). P. loosi is a serious pest of tea (Camellia sinensis). Besides tea, it has also been found in association with several important crops such as apples in Sri Lanka, Japan and China, citrus in Japan, India and Iran, pears, Convallaria and natural grasses in Japan, coffee in Java, fruit trees in China, breadfruit (Artocarpus altilis) in Gualdeloupe, pasture grasses in Florida, cabbage in Kenya and bananas in American Samoa (Seinhorst, 1977; Inserra et al, 1996; Ekanayake and Toida, 1997; Brooks, 2004; Castillo and Vovlas, 2007; Waceke, 2007; Divsalar et al, 2012). P. loosi invades the roots where it reproduces, feeds and moves freely in the tissues. When the nematodes invade the roots, they cause thickening of the cell walls, dark brown or black necrotic lesions, and cavities. When the nematodes are searching for fresh feeding roots, or when the parasitised roots are severely damaged or overparasitised, or when the plants are old, stressed or diseased, the nematodes leave the roots and move into the soil. P. loosi has been known to survive for up to three years in host‐free soil in the lesions of the larger old storage roots of tea that are not removed after clearing old tea fields (Gnanapragasam and Mohotti, 2005). The optimum temperature for P. loosi development is 18–20°C; it requires 45–48 days to complete its life cycle (Seinhorst, 1977). The presence of plants such as Tephrosia vogelii, Sesbania cinerascens, Cassia elata and Acacia spp., as well as certain weeds increases the occurrence of this nematode species in the tea field. On the other hand, plants like Eragrostis curvula, Tagetes spp., Arachis pintoi, Tithonia diversifolia, Wedeliya trilobata, Vetiveria ziazanoides, Adhathoda vasica, Ricinis communis, Azadirachta indica, Madhuca indica, Sambucus javanica, Plectranthus zeylanicus, Indigofera teysamanii, Eupatorium inuliformes, Calliandra calothyrsus and Crotalaria anagyroides reduce the population density of this nematode (Gnanapragasam and Mohotti, 2005). Turkey’s replies to the questions posed by the Working Group state that P. loosi has been detected in limited areas in very low populations in potatoes, eggplants, wheat and lentils. So far, this species has not been found on apples in Turkey and no damage by it or other Pratylenchus species to fruit crops has been observed. According to the available information, the nematode has been reported on cultivated plants in Turkey in two regions (Sanliurfa, Ankara) (Yavuszlangolu et al., 2012; Kasapoglu Uludamar et al, 2018). No epidemics or economic losses have been reported in Turkey so far.
Symptoms	Main type of symptoms	The above‐ground symptoms of Pratylenchus spp. infestation are not very specific. They appear as irregular, patchy areas while the plants wilt, become stunted, chlorotic, and often die. Symptoms caused by root lesion nematode infestation are more obvious on the roots, where dark brown or black necrotic lesions are observed on the root surface.
	Presence of asymptomatic plants	In general, symptoms caused by Pratylenchus spp. on plants are inconspicuous and can be easily overlooked. P. loosi may also go undetected if the nematode infestation in the roots of host plants is low (symptoms are not very pronounced). The nematode may therefore not be detected by existing phytosanitary procedures and export controls, including laboratory tests. In Turkey (see Turkish dossier), roots are examined macroscopically only for the presence of root galls caused by root‐knot nematodes (Meloidogyne spp.). Necrotic lesions caused by root‐lesion nematodes are not monitored.
	Confusion with other pathogens/pests	Symptoms of host plant infestation by P. loosi are expressed as reduced plant growth and vigour with moderate root necrosis. Typical above‐ground symptoms such as stunting, chlorosis and wilting result from reduced water and nutrient availability due to impaired root function. Therefore, these symptoms are similar to those of other soil‐borne diseases, insect damage, nutrient deficiency, or cultural and/or environmental stress. The most characteristic sign of a nematode problem in the field is often an irregularity or inconsistency of symptoms. However, yield losses can also occur without noticeable above‐ground symptoms. Symptoms on the underground parts of the plant can be more informative, but care must be taken to diagnose the cause of the symptoms. Many common symptoms, such as necrotic lesions, are also characteristic of damage caused by other root lesion nematodes. P. loosi can easily be confused with other Pratylenchus species.
Host plant range	Camellia sinensis (tea) is the main host of Pratylenchus loosi (CABI Plantwise Knowledge Bank, online). Other hosts that may be affected (CABI Plantwise Knowledge Bank, online): Abelmoschus esculentus (okra), Acacia decurrens (green wattle), Alternanthera sessilis (sessile joyweed), Artemisia vulgaris (mugwort), Cassia alata (Ringworm senna), Catharanthus roseus (Madagascar periwinkle), Cestrum (jessamine), Cinnamomum camphora (camphor laurel), Citrus, Coffea (coffee), Convallaria, Cymbopogon citratus (lemongrass), Cyperus (flatsedge), Cyperus rotundus (purple nutsedge), Dioscorea (yam), Dioscorea rotundata, Diospyros kaki (persimmon), Dipteryx odorata (tonka bean), Fragaria ananassa (strawberry), Grevillea robusta (silky oak), Hibiscus rosa‐sinensis (China‐rose), Imperata cylindrica (cogon grass), Malus domestica (apple), Mangifera indica (mango), Musa x paradisiaca (plantain), Oplismenus compositus, Panicum hemitomon, Panicum repens (torpedo grass), Paspalum notatum (Bahia grass), Pisum sativum (pea), Poncirus trifoliata (Trifoliate orange), Prunus avium (sweet cherry), Pyrus communis (European pear), Saccharum officinarum (sugarcane), Sesbania cannabina (corkwood tree), Solanum nigrum (black nightshade), Solanum tuberosum (potato), Sorghum bicolor (sorghum), Tagetes (marigold), Tecoma stans (yellow bells), Tephrosia (hoary‐pea), Tithonia diversifolia (Mexican sunflower), Vigna unguiculata (cowpea), Zea mays (maize).
Reported evidence of impact	P. loosi is known as a major pest of tea (Camellia sinensis) in Sri Lanka and many other tea‐producing countries including India, Japan, Korea, Taiwan, Iran and Russia (Luc et al. 2005; Castillo & Vovlas, 2007; Handoo et al., 2008). It is considered an important pest of tea grown at altitudes from 900 to 1800 m in Sri Lanka and from 0 to 300 m in Japan. P. loosi can seriously damage tea plantations by attacking not only the existing feeder roots and causing their slow decline, but also the main roots (storage roots) of tea plants, limiting nutrient and water uptake from the soil as well as
	carbohydrate reserves and subsequent recovery after pruning (Gnanapragasam, 2002; Castillo and Vovlas, 2007). Tea plants become weaker and chlorotic, have lower yields and may also die. Yield reduction can vary from 4 to 40% depending on the variety planted, prevailing climatic conditions, population density of nematodes, age and vigour of plants, soil type and pH. The extent of damage is greater in young infested tea plantations and nurseries where damage of 60 to 100% may occur if proper control measures are not taken (Gnanapragasam and Mohotti, 2005). This nematode has also been reported as a pest of pasture grasses and oranges (Singh et al., 2013; Disvalar et al., 2012). Poorer growth of Unshiu oranges in Japan (Ushiyana & Ogaki, 1970) and yellowing and reduction of leaves and necrotic lesions on parasitised roots of citrus trees in the southwest of Caspian Sea in Iran (Divsalar et al., 2012) have been reported. Unfortunately, no detailed information is available on the economic impact on grasses, oranges and other host plants except tea. Since P. loosi causes necrotic lesions on the roots, secondary infections by bacteria and fungi that further damage the root system are very common. The synergistic effect of interaction between P. loosi and soil‐borne root fungi (e.g. Rhizoctonia solani, Fusarium proliferatum, F. pallidoroseum, Sclerotium rolfsii) was reported in 2010 by Hoseini et al. The occurrence of soft root rot on mature tea roots was also reported, leading to death of affected plants in dry weather. The disease complex caused by P. loosi and a group of fungi Paecilomyces lilacinus, Paecilomyces sp. and Absidia corymbifera was also reported (Gnanapragasam and Mohotti, 2005).
Pathways and evidence that the commodity is a pathway	–Plants, plants for planting (roots) –Soil and growing media as such or attached to plants –Soil and growing media attached to machinery, tools, packaging materials. etc.
Surveillance information	In order to identify plant pests and diseases in the planting material to be exported from Turkey, a minimum of 5 and a maximum of 25 saplings are taken at random from the planting in the nursery, sealed by the inspector and sent to the laboratory for analysis. The saplings in the growing area are examined macroscopically for pests. If pest infestation is suspected, samples are again taken and sent to the laboratory for analysis.