Meloidogynidae

Meloidogynidae is a family of plant-parasitic nematodes within the order Tylenchida. The family is best known for the genus Meloidogyne, whose species are collectively called root-knot nematodes due to the galls they induce on roots. Members are sedentary endoparasites of a wide range of host plants and are among the most economically damaging plant pathogens worldwide.

Life cycle and biology: Females enter roots and establish feeding sites called giant cells; they remain fixed as the roots grow, producing root galls or knots on the roots. Eggs develop into second-stage juveniles (J2), the primary dispersal and infective stage, which hatch in soil and invade roots. Many species reproduce by parthenogenesis, though some reproduce sexually.

Distribution and host range: They are cosmopolitan, most abundant in warm or temperate climates, and occur in agricultural soils worldwide. Host plants span vegetables, fruits, cereals, and ornamentals, with symptoms including stunting, yellowing, and reduced yields resulting from impaired water and nutrient uptake.

Diagnosis and management: Identification combines symptom observation, nematode extraction from soil or roots, and morphological or molecular methods; the female perineal pattern is a traditional diagnostic feature, while molecular assays provide precise species identification. Management includes crop rotation with non-hosts, resistant cultivars, soil solarization, selective nematicides where permitted, and biological control.

Taxonomy and notes: Meloidogynidae comprises the root-knot nematodes, with Meloidogyne as the best-known genus. Taxonomic placement has evolved with molecular data, but the group remains a major focus of plant-nematode research.