Lemon root-knot nematode

The lemon root-knot nematode (Meloidogyne limonae) is a parasitic roundworm belonging to the order Tylenchida and the family Meloidogynidae. As an endoparasite, it colonizes the roots of citrus plants, creating specific physiological changes that manifest as visible galls on the root system.

This pest primarily infests citrus species, particularly lemons. It thrives in warm, moist soils, making citrus-growing regions highly susceptible. The nematode's ability to remain in the soil makes it a persistent challenge for both orchard management and nursery plant production.

The biological cycle starts with the juvenile stage, where the nematode migrates through the soil to find a suitable root host. Once it enters the root, the nematode becomes sedentary. The female matures, swells into a pear-like shape, and produces large quantities of eggs embedded in a protective gelatinous matrix within the root tissue.

Damage to the plant is caused by the disruption of water and nutrient uptake through the root system. Key symptoms and impacts include:

• the formation of characteristic knots or galls on roots;
• stunted plant growth and overall loss of vigor;
• chlorosis and premature foliage drop;
• reduced fruit quality and yield;
• increased susceptibility to drought stress and soil pathogens.

Effective control strategies focus on prevention and integrated pest management (IPM). Growers should prioritize the use of certified nematode-free planting stock. Soil solarization or steaming, the use of cover crops that suppress nematode populations, and the application of biological nematicides are essential components for managing Meloidogyne limonae in citrus production systems.