Indian root-lesion nematode

Systematic position and general characteristics: The Indian root-lesion nematode (Pratylenchus indicus) belongs to the phylum Nematoda, family Pratylenchidae. It is a migratory endoparasitic nematode recognized as a significant agricultural pest that inhabits the root tissues of various crops, causing severe damage by disrupting vascular functions.

Diseases and host plants: This pathogen is primarily associated with root rot and reduced plant vigor in rice paddies. Beyond rice, Pratylenchus indicus has a broad host range, including maize, sorghum, and wheat, as well as various wild grasses that serve as hosts, enabling the nematode to survive between cropping seasons.

Biology and lifecycle: The lifecycle of Pratylenchus indicus is characterized by several stages, including eggs, four juvenile stages, and adults. Both juveniles and adults act as active endoparasites. They enter the cortical tissue of roots, where they feed on the cytoplasm of cells, leading to the formation of characteristic lesions that serve as entry points for secondary soil-borne fungi and bacteria.

Developmental conditions and economic impact: The nematode thrives in moist, well-aerated soils with moderate to high temperatures. Its economic impact is significant, particularly in intensive rice production systems. Infested plants exhibit stunted growth, yellowing (chlorosis), and reduced tiller development, which often results in substantial yield losses due to impaired water and nutrient uptake.

Protection and control measures: Effective management of Pratylenchus indicus requires a multi-faceted approach to minimize population levels in the soil. Recommended practices include:

• Implementing crop rotation with non-host species to disrupt the nematode's lifecycle.
• Application of chemical nematicides in high-risk areas during land preparation.
• Using nematode-resistant or tolerant crop varieties.
• Maintaining field hygiene, including the removal of infected plant debris and weeds.