NAME OF THE ORGANISM: Pratylenchus vulnus (PRATVU)

Evaluation continues

Candidate

Pratylenchus vulnus had a more limited host range compared to P. penetrans (PlantwisePlus Knowledge Bank 2023; aaltjesschema, 2019). It has been reported on e.g. Pistacia vera (Pinochet et al., 1992), Malus and Pyrus (Fernandez et al., 1992), Cydonia (Calvet et al., 1995), Ficus carica (Plantwise Knowledge Bank, 2023). Prunus species are important hosts of Pratylenchus vulnus (Plantwise Knowledge Bank, 2023), e.g. Prunus armeniaca (Askary et al., 2012), Prunus domestica (CABI, 2021), Prunus persica (Simeone, 1993), Prunus dulcis (UC-IPM, 2019). Pratylenchus vulnus has also been reported from Fragaria, but mainly from Asia (Mohotti et al, 1997, Ko et al., 2017; Wakibe H, Ito F & Higashizima), Australia (Colbran, 1974) and Uruguay (Minagawa & Maeso-Tozzi, 1990).
Pratylenchus spp. are migratory endoparasites that enter the host root for feeding and reproduction and move freely within the tissue. Consequently, they spend much of their life cycle in roots and are found in soil when the host plants are senescing, stressed or diseased, or when their hosts have been ploughed up after harvest (Castillo and Vovlas, 2007).
The transport of infected plants or those growing in infested soils is one of the principal means by which these nematodes are disseminated (Lehman, 1994; Anonymous, 1999). Bare-rooted plants are often contaminated by soil particles which may contain nematodes. Roots can host endoparasitic nematodes that are not removed by washing treatments (Lehman, 1994). In this context, it is essential that the plant propagation material be free of this pathogen (Allen, 1949).
Pratylenchus vulnus can also be spread by equipment and other human activities that can move soils from infested to non-infested sites. The nematodes can also be spread by drainage, irrigation, or flood water (Corbett, 1974). These pathogens are readily disseminated when field runoff water used in irrigation is reused in other fields (Lehman, 1994). In Spain, Pratylenchus were found in 60% of the samples from irrigation canals where they sampled (Tobar y Palacios, 1974). However, measures (including hygiene) can limit the importance of other pathways than plant for planting. In particular, according to Lehman (1994), most of the damage to fig, peach and olive crops caused by Pratylenchus vulnus could be prevented with sanitation and certification programs that produce nematode-free seedlings.
On its own, Pratylenchus species can move 1-2 m per season from an infected root.
Considering the numerous bibliographic references that highlight the importance of plants for planting as an important pathway, and the existence of measures that can reduce the role of the others reported pathways, host plants for planting with roots, with or without soil or growing media, are considered as a main pathway.

Yes

Although quince (Cydonia oblonga) is a suitable host, it appears to be less susceptible to P. vulnus than apple and pear rootstocks (Fernandez et al. 1992).

Pratylenchus vulnus is associated with replant problems in pome and stone fruit trees. It is estimated that the losses caused by this pest worldwide in fruit species is around 5% on average, although in specific situations, in plantations with high infestations, losses can exceed 30%. These losses are not manifested in tree mortality, but in a decrease in production and smaller fruit size (Pinochet, 2011). Pathogenicity studies conducted in Spain and France indicate that Pratylenchus vulnus is damaging to apple, pear, quince and several Prunus rootstocks including plum (references in Pinochet et al., 1998).

It is worth mentioning that it is difficult to accurately measure the damage that these nematodes can cause because infested roots are normally invaded by soil microorganisms, mainly secondary fungi and bacteria, which contribute to promote root tissue rotting and masking the effect of the primary pathogen (Pinochet, 2011).

Medium to Major

No

Candidate

There are reports confirming the economic impact of this pest on the crop. In addition, Spanish experts from the field considered that the effects of this nematode on quince are significant.
The damage caused by Pratylenchus is usually most severe in light-textured soils that are low in nutrients (e.g. nitrogen, potassium, or calcium) and in organic matter (Anonymous, 1999).

Candidate

The propagation material is kept either in containers of sterilized growing medium or in soil that has been tested and found free from Pratylenchus vulnus (PM4/17-3)
Propagation of rootstock on fields which are tested and found free of nematodes.

Fallowing or sowing cereals: it is advisable to leave the land selected for cultivation for 1-2 years (preferably without weeds) or to sow cereals in the season prior to the establishment of the orchard. Both practices are relatively effective in reducing nematode populations in the soil by starvation (Pinochet, 2011).

Disinfection of plant material: recommended practice for nurseries and commercial plantations. It consists of immersing the seedlings (bare root) in hot water (40 - 50ºC) for 10-30 min. It has been successfully used to disinfect cherry, peach and apple seedlings, and is applicable to most fruit species. Another alternative practice with good results is the immersion of roots in an aqueous solution with nematicide. The cost of both operations is usually high (Pinochet, 2011).

Candidate