Wheat seed gall nematode

Taxonomic position and pathogen type. The wheat seed gall nematode (Anguina tritici) belongs to the kingdom Animalia, phylum Nematoda, family Anguinidae. It is a specialized plant-parasitic nematode that acts as an obligate pathogen. Unlike fungal diseases, this organism is a microscopic worm that creates specific gall structures within the spikes of cereal plants, representing one of the first plant-parasitic nematodes ever described.

Diseases and host crops. This pathogen causes the condition known as wheat ear cockle or seed gall. Its primary host is wheat (Triticum aestivum), although it can also infest rye and spelt. The infestation manifests as the replacement of healthy grain kernels with dark, hard galls, leading to significant morphological changes in the wheat head and a drastic reduction in grain quality.

Biology and life cycle. The life cycle of Anguina tritici is highly synchronized with the host plant's growth. Larvae survive in a dormant state inside galls found in the soil or stored grain. Upon contact with moisture, larvae emerge, migrate up the host plant stem, and invade the developing floral tissues. Inside the spikelet, they induce gall formation, mature, and lay eggs, ensuring the next generation is ready for dispersal during harvest.

Development conditions and damage. Development is favored by high humidity and moderate temperatures during the early stages of wheat tillering. The damage is primarily economic: the crop yield is severely reduced because the galls contain no starch or flour. Furthermore, the presence of galls is often associated with the secondary transmission of the bacterium Clavibacter tritici, which causes the more severe disease known as "yellow slime" or "tundu".

Protection and control measures. Management focuses on prevention and sanitation. Using nematode-free certified seeds is the most effective control method. Since nematode galls are lighter than healthy seeds, they can be separated by floating the seeds in a brine solution (e.g., a salt or specific gravity water bath). Crop rotation, leaving a two-year gap between cereal crops, effectively breaks the nematode's life cycle in the field, as larvae cannot survive indefinitely without a host.