Because of molecular pathways conservation between worms and humans, design of “human safe” nematicides requires precise drug targeting
Phytoparasitic nematodes are found in a great diversity of plants and crops throughout the world, causing important economic losses. According to their life cycle and feeding behavior, they are classified into 3 groups:
Endoparasites: They penetrate inside the plant, where all or part of its life cycle takes place. In general, they are very pathogenic because their feeding behavior inside the plant tissues interferes on the absorption of both water and nutrients. Some examples are root-knot nematodes (Meloidogyne spp.), cyst nematodes (Heterodera spp., Globodera spp.), root-lesion nematodes (Pratylenchus spp., Hirschmanniella spp., Radopholus spp.), stem nematodes (Ditylenchus spp.), and the pine wood nematode Bursaphlenchus xylophilus.
Ectoparasites: Their life cycle is developed entirely outside the plant, perforating the epidermis or the superficial layers of the host plant root cortex with the stylet. Some ectopararasitic nematodes can act as virus vectors, causing important plant diseases (Xiphinema spp., Trichodorus spp.,Paratrichodorus spp.)
Semiendoparasites: These can partially penetrate the plant, with one part of the nematode inside the plant and the other part outside, carrying out the egg-laying towards the outside, e.g., Sphaeronema spp., Hoplolaimus spp., and Helycotylenchus spp. [Mesa-Valle et al 2020]
Conventionally, the most used control method against plant-parasitic nematodes has been soil chemical fumigation. An effective nematode control was achieved by the use of methyl bromide (MB). The use of this product has been banned in advanced countries since 2005 because of stratospheric ozone depletion. After the ban on the use of MB and the revocation of 1, 3-dichloropropene in European Union (EU) countries, the control strategies aim to reduce soil nematode population levels to below the tolerance threshold of the crop; they integrate chemical nematicides, bionematicides (mainly based on fungi or bacteria), physical methods (soil solarization, heating sterilization, ozone treatments) and/or agronomic practices (crop rotation, use of resistant varieties or nematicidal plants, anaerobic soil disinfection, green manures, biofumigation, soil amendments). The design of these strategies will be based on knowledge of the biology of the parasite.