Measurements
Related invasive species
- Anguina tritici
Related Farm Practice
- Hosts
- Host plants
Anguina tritici, commonly referred to as wheat seed gall nematode, is the cause of ear-cockle disease. It was the first plant-parasitic nematode to be described in the scientific literature in 1743. Its host range includes wheat, triticale, rye, and related grasses;the primary host is wheat. Ear cockle in the past was reported in all major wheat growing areas. However, physical and mechanical methods for separating infected galls from seed have eradicated the nematode from the western hemisphere. It remains a problem in several countries in the Near and Middle East, the Asian Subcontinent and Eastern Europe, most likely due to poor awareness and lack of campaigns for establishing clean seed. A. tritici is on the U.S. Pests of Economic and Environmental Importance List, and on the ‘Harmful Organism Lists’ for Argentina, Brazil, Chile, Colombia, Ecuador, Egypt, Guatemala, Indonesia, Israel, Madagascar, Namibia, Nepal, New Zealand, Paraguay, Peru, South Africa, Taiwan, Thailand, Timor-Leste and Uruguay.
The absence of symptoms does not mean absence of A. tritici (Thorne, 1949). Slight elevations occur on the upper leaf surface with indentations on the lower side. Other symptoms include wrinkling, twisting, curling of the margins towards the midrib, distortion, buckling, swelling and bulging. A tight spiral coil evolves, and dwarfing, loss of colour or a mottled, yellowed appearance and stem bending may also occur (Byars, 1920;Leukel, 1924). In severe infection, the entire above-ground plant is distorted to some degree and a disease problem is usually obvious.
Heads (spikes)
Wheat heads are reduced with glumes protruding at an abnormal angle exposing the galls to view. This does not occur in rye heads.
Galls
Young galls are short-thick, smooth, light to dark green, turning brown to black with age, 3.5-4.5 mm long and 2-3 mm wide. Rye galls are small, buff-coloured and longer than wide, 2-4.5 mm long by 1-2.5 mm wide (Byars, 1920;Leukel, 1924).
A. tritici is highly specialized with a narrow host range. Significant multiplication only occurs on wheat or closely related plants. Many common grasses have been exposed to A. tritici;most have been shown to be non-hosts (Leukel, 1957).
Oat and Polypogon monococcum are poor hosts (Southey, 1972). A. tritici invades and multiplies in maize tissue, but does not complete its life cycle in this plant (Limber, 1976).
In addition to the hosts listed in the table, Alopecurus monspeliensis and Lolium temulentum (Dahiya and Bhatti, 1980), Holcus lanatus and Phleum pratensis (Filipjev and Schuurmans Stekhoven, 1941), and Triticum monococcum (Southey, 1972) are also reported as hosts of A. tritici.