Wheat seed gall nematode

The wheat seed gall nematode (scientific name Anguina tritici) is a destructive plant-parasitic nematode that specifically targets wheat and some other cereals. It belongs to the family Anguinidae. As a specialized pathogen, it does not kill the host plant directly but redirects its resources, leading to the formation of characteristic galls in the ear instead of healthy kernels.

The disease caused by this pathogen is known as ear cockle or seed gall disease. During the plant's development, the larvae migrate to the floral primordia. Once inside, they induce the plant to form a hard, dark-brown, seed-like gall. These galls are filled with thousands of second-stage larvae in a state of suspended animation, allowing the nematode to survive harsh environmental conditions for several years.

The biological life cycle of Anguina tritici is synchronized with the phenology of the host plant. When infected seeds are sown, the humidity in the soil triggers the larvae to emerge from the galls. They move along the stem of the seedling to the growing point. As the wheat progresses through its growth stages, the nematodes infest the developing spikelets, eventually replacing the ovaries with the gall structures containing the next generation of larvae.

Development and spread are heavily dependent on moisture levels during the germination phase. The primary method of transmission is through contaminated seed lots. If the seed cleaning process is insufficient to remove the galls, the parasite is effectively distributed throughout the field. Secondary movement can occur via soil moisture, rainfall runoff, or farm equipment moving between fields.

Economic damage is caused by yield loss and potential toxicity issues if galls are mixed with grain used for livestock feed. Management and control strategies focus on sanitation and cultural practices:

• Utilizing certified, nematode-free seed stock.
• Implementing a crop rotation cycle for 2 to 3 years with non-host crops to starve the population.
• Employing density-based seed cleaning equipment to separate galls from healthy grain.
• Deep plowing to bury infested crop residues, preventing larval emergence.