Thorne's lesion nematode

Taxonomic classification: Pratylenchus thornei is a migratory endoparasitic nematode belonging to the family Pratylenchidae. Unlike sedentary nematodes, this species moves continuously through the root cortex, feeding on cells and creating tunnels as it develops, which results in significant damage to the plant's vascular system.

Diseases and host plants: This nematode is a major cause of root lesion disease. Its primary hosts include wheat, barley, chickpeas, and various legumes. By feeding on root cells, the nematode causes necrosis, leading to stunted plant growth, chlorosis, and reduced water and nutrient uptake, which often resembles drought stress symptoms.

Biology and life cycle: The life cycle involves eggs laid in the soil or root tissue, followed by four juvenile stages and the adult stage. Both juveniles and adults can cause damage. The nematode thrives in various soil types, and it can survive harsh conditions by persisting in crop residues or dormant roots of perennial weed hosts, making it difficult to eradicate completely.

Conditions and impact: Pratylenchus thornei population densities increase rapidly under favorable moisture and temperature conditions, typically ranging from 15°C to 25°C. The economic impact is severe, as it reduces grain yield and quality. Affected crops are often unable to recover even with adequate fertilization, as the root structure is compromised by extensive tissue degradation.

Protection and control measures: Management of this pathogen requires an integrated approach due to the limitations of chemical nematicides.

• Implementing crop rotation with resistant or non-host crops to starve the nematode populations.
• Selecting cultivars with genetic resistance or tolerance to P. thornei.
• Effective weed management to eliminate alternative hosts throughout the growing season.
• Ensuring optimal field hygiene and preventing the movement of infested soil between agricultural zones.