Paddy Root-Knot Nematode

📖 Description

Paddy Root-Knot Nematode (Meloidogyne graminicola) is the most important nematode pest of rice in the Indian subcontinent, particularly severe in upland rice, direct-seeded rice and rice-wheat rotation systems of Uttar Pradesh, Bihar, West Bengal, Odisha, Chhattisgarh, Madhya Pradesh and Assam. Unlike other root-knot species (M. incognita, M. javanica) which mainly attack dicots, M. graminicola is specialized for grasses including rice, wheat and many weeds. The pest causes characteristic hook-shaped or spiral galls on rice roots that interfere with water and nutrient uptake, leading to stunting, yellowing and reduced tillering. The pest is particularly damaging in nurseries (where seedlings can be killed) and in upland/direct-seeded rice (where flooding cannot suppress populations). Outbreaks are favoured by sandy soils, continuous rice cropping and rice-wheat rotation (wheat is also a host). IPM with biocontrol (Paecilomyces lilacinus), organic amendments, resistant varieties and crop rotation provides effective suppression. Flooding between crops can suppress nematode populations by creating anaerobic conditions — a unique advantage of lowland rice systems that should be exploited.