Ring nematode

Systematic position: Hemicriconemoides pseudobrachyurus belongs to the phylum Nematoda, class Chromadorea, order Rhabditida, and family Criconematidae. It is recognized as an obligate plant-parasitic nematode that predominantly occupies the rhizosphere and feeds ectoparasitically on the roots of various host plants.

Host crops: This nematode has a diverse host range, impacting various woody perennials and agricultural crops. It is frequently associated with citrus trees, grapevines, peaches, and other fruit-bearing species. Additionally, it has been recorded on several agronomic crops such as maize and peanuts, causing significant root system decline.

Biology and life cycle: The life cycle consists of the egg, four juvenile stages, and the adult stage. The nematodes are sedentary ectoparasites, often found attached to the root surface. They use a specialized stylet to penetrate root epidermal cells, facilitating nutrient uptake from the host. Survival in the soil depends on soil moisture and root availability.

Damage and pathogenicity: The primary damage is caused by the physical destruction of root cells during feeding, which leads to the formation of necrotic lesions. Secondary infections by soil-borne pathogens often aggravate the primary damage. Affected plants typically show signs of stunting, chlorosis, reduced vigor, and significant yield losses, especially under stress conditions.

Control measures: Management of H. pseudobrachyurus focuses on integrated pest management (IPM) practices. Key strategies include:

• Utilizing nematode-free planting stock.
• Implementing crop rotation with non-host crops.
• Enhancing soil health through the application of organic amendments.
• Applying chemical nematicides only when populations exceed established economic thresholds.