Citrus lesion nematode

Taxonomy: The citrus lesion nematode Radopholus citri is classified within the phylum Nematoda, class Chromadorea, order Tylenchida, and family Pratylenchidae. It is recognized as a migratory endoparasite that primarily invades the cortical tissues of host roots.

Host plants and damage: The species is a significant pest of various citrus species. By feeding on the internal tissues of the roots, it causes the destruction of the cortical cells and interferes with the root system's ability to transport water and essential nutrients from the soil to the aerial parts of the plant.

Biology and life cycle: The life cycle of Radopholus citri is completed in several weeks, depending on environmental conditions. It includes eggs, four larval stages, and adults. Both juveniles and adults migrate through the root cortex, leaving behind galleries of dead cells, which effectively disrupts root functionality.

Symptoms of infestation: Infested trees typically exhibit reduced vigor, yellowing of foliage (chlorosis), stunting, and significantly decreased fruit production. Above-ground symptoms are usually the result of the root system failing to support the canopy, which may eventually lead to tree decline or dieback under stress conditions.

Protection and management: Integrated management is the most effective strategy. Key practices include:

• Use of nematode-free planting material verified by testing.
• Selection of citrus rootstocks that demonstrate tolerance or resistance to nematode damage.
• Implementation of strict phytosanitary measures to prevent the spread of infested soil.
• Application of bio-nematicides or soil amendments that promote natural antagonists in the rhizosphere.
• Periodic monitoring of soil nematode populations in commercial orchards.