Lusitanian root-knot nematode

Systematic position: Meloidogyne lusitanica is a member of the order Tylenchida and the family Meloidogynidae. It is a highly specialized sedentary endoparasitic nematode that spends the majority of its life cycle within the roots of its host plants, inducing physiological and anatomical changes.

Host range: This nematode species is known for its polyphagous nature. It significantly affects plants from the Solanaceae family (such as tomatoes and eggplants) and is particularly notorious for its impact on olive trees (Olea europaea), where it contributes to severe root system degradation and plant decline.

Biology and life cycle: The life cycle involves the egg stage, four larval stages, and the adult form. Infective second-stage juveniles (J2) migrate through the soil to locate roots, penetrate them, and establish permanent feeding sites by inducing the formation of giant cells. Adult females become swollen and sedentary, remaining within the root tissue while laying masses of eggs embedded in a protective gelatinous matrix.

Damage and severity: The primary symptom of infestation is the formation of galls (knots) on the roots, which disrupt water and nutrient uptake. Infected plants often show stunted growth, leaf chlorosis, wilting during hot weather, and significantly reduced yield. In the case of olive trees, root decay caused by Meloidogyne lusitanica often leads to poor plantation establishment and tree death.

Control measures: Management of this nematode is challenging and requires an integrated approach to maintain population levels below the economic threshold:

• Strict nursery hygiene and the use of nematode-free planting material.
• Crop rotation with non-host or antagonistic crops, such as Tagetes or mustard varieties.
• Application of biological control agents, including specialized nematophagous fungi and rhizobacteria.
• Soil solarization or steaming techniques to eliminate nematode populations in enclosed environments like greenhouses.