Anguina tritici

1. Symptoms: Distorted leaves and stems are evident prior to heading. Plants can be stunted, and increased tillering may occur. As diseased plants approach maturity, galls are formed in the florets, replacing the kernels (picture at left). The galls are similar in shape to the seed they replace and are black (initially dark green) in color (picture at right). Large numbers of motile larvae are present within the galls and become active after the galls have been moistened. These nematodes can act as vectors of the bacterium Corynebacteriurn tritici.
2. Development: Seed galls are dispersed along with seed during planting and harvest. In moist soil, seed galls release thousands of larvae. Wet weather favors larval movement and the infestation process. The nematode invades the crown and basal stem area, finally penetrating floral primordia. There they mature and produce large numbers of eggs. Seed galls develop in undifferentiated floral tissues.
3. Hosts/Distribution: The seed gall nematode parasitizes wheat, barley, triticale, rye, and related grasses; it affects wheat primarily. It is found in the Near and Middle East, the Asian Subcontinent, and Eastern Europe. Populations in Australia, Europe, and North America have become locally extinct due to farming practices.
4. Importance: This nematode rarely is of economic importance, though yield loss can become severe (up to 50%), depending on the population density. Seed hygiene is a major method of control for these nematodes.

Reference:

• Dr. Ian T. Riley- Nematologist, University of Adelaide, South Australia.