Rice stem nematode

The rice stem nematode (Ditylenchus angustus) is a destructive plant-parasitic nematode belonging to the order Tylenchida and the family Anguinidae. It is recognized as a major threat to rice production in various parts of Asia, causing the famous "ufra" disease, which results in severe yield reduction and crop failure.

This parasite primarily targets the rice plant (Oryza sativa) at various growth stages. It is highly adapted to aquatic environments, where it moves through the thin film of water on rice stalks, invading the developing tissues of the plant and consuming the sap through its specialized mouthpart called a stylet.

The biology of Ditylenchus angustus is characterized by its ability to survive harsh conditions. When the field dries up, the nematodes enter a state of cryptobiosis, becoming dormant and resistant to desiccation. They can remain viable in crop residues, soil, or even seeds for an extended period until water returns to the environment.

Damage symptoms usually appear as discoloration, chlorosis, and severe twisting of leaves. In advanced cases, the stem exhibits brown, necrotic lesions. Since the nematode feeds on developing inflorescences, the main impact is the failure of the panicle to emerge properly, resulting in sterile grains or shriveled seeds that significantly reduce the total yield.

• Planting certified nematode-free rice seeds.
• Implementing crop rotation with non-host species to break the life cycle.
• Removing and destroying infected crop stubble to eliminate overwintering sites.
• Managing irrigation systems to prevent the flow of infested water to healthy fields.
• Breeding and planting rice varieties known for their natural resistance.