Grass seed nematode

Systematic position: The grass seed nematode (Anguina agrostis) is a plant-parasitic nematode belonging to the order Tylenchida and the family Anguinidae. It is a highly specialized parasite that specifically targets the reproductive structures of grasses, leading to the formation of seed galls instead of healthy kernels.

Host plants: This nematode primarily infests a wide range of grasses, including bentgrass (Agrostis spp.), fescue (Festuca spp.), bluegrass (Poa spp.), orchardgrass (Dactylis glomerata), and various other perennial grass species. Its economic significance is highest in seed production fields where quality standards for seed purity are critical.

Biology and life cycle: The life cycle is synchronized with the grass host. Second-stage juveniles overwinter within desiccated galls. During wet spring conditions, they emerge and migrate onto the developing plant shoot, eventually reaching the floral buds. They feed on the developing ovaries, inducing gall formation, within which they undergo several molts to reach the adult stage.

Damage and economic impact: The hallmark symptom is the presence of brown or black galls that replace the normal seeds in the spikelet. These galls are structurally different from normal seeds, being lighter and shorter. Significant infestations result in substantial yield losses, compromised seed germination, and potential rejection of harvested crops due to the presence of nematode-infected galls.

Management and control: Integrated pest management is essential for controlling this nematode.

• Use certified, nematode-free seed lots for planting.
• Implement strict crop rotation schedules avoiding susceptible grass hosts for at least 2–3 years.
• Practice deep plowing to bury plant debris and infested soil residues.
• Employ hot water seed treatment (50–55°C) if contamination is suspected, as heat effectively eliminates the juveniles residing inside the galls.