Anguina tritici is not vectored by another species.

Anguina tritici, however, is the vector of the bacterium Clavibacter michiganese pv. tritici , which is the causal agent of a spike blight known as yellow ear rot or "tondu" of wheat (Bridge and Starr, 2007). Freshly harvested infected wheat cockles containing the bacterium are toxic to cattle and sheep (Anwar et al., 2001).

Method	Instructions	NAPIS Survey Method
Tissue Sample	Collect a seed sample coupled with visual survey of the seed for galls and irregular seed.	3011 - General Tissue Sample

Baerman funnels and flasks/shakers have been used for nematode emergence/ extraction from the wheat galls in water. The seeds can also be directly dissected to release nematodes into water. Any nematodes that emerge from seed will need to be confirmed using morphological/ molecular methods.

Note: It is possible that surveys for Anguina tritici could occur in conjunction with surveys for karnal bunt in wheat.

The nematodes themselves can be seen when the seeds are soaked in water and dissected or extracted using other methods.

Ectoparasitic feeding of A. tritici may cause leaf rolling, curling, and spiraling (Anwar et al., 2001). Severe infection of young plants can result in stunted plants with distorted, misshapen stems and leaves (Bridge and Starr, 2007). The ear or inflorescence may be absent or, when present, wider and shorter (Bridge and Starr, 2007). Plants mature more slowly, and produce smaller seed heads. Yield depressions of 50% are common (Ferris, 2013). Infected wheat heads are reduced with glumes protruding at an abnormal angle exposing the galls to view. This does not occur in rye heads (Ferris, 2013).

Infected seeds are transformed into galls that are light brown to nearly black in color. Galls contain a white powdery mass that consists of dry nematodes in an anhydrobiotic state (Bridge and Starr, 2007). Galls appear darker, shorter, and thicker than seed kernels. 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-colored and longer than wide, 2 - 4.5 mm long by 1 - 2.5 mm wide (Leukel, 1924; Byars, 1920).

ID/Diagnostic: Multiple

Initial diagnosis will be via morphology. All initial diagnoses will need to be confirmed with molecular methods.

A dichotomous key has been developed to identify Anguina tritici (Krall, 1991) that uses many morphological and biological characteristics.

Although not officially validated for regulatory purposes, Li et al. (2015) demonstrated PCR primer pairs that target specific areas of the ITS1 region and are able to differentiate A. tritici from A. agrostis , A. funesta , and A. pacificae (Li et al., 2015). The PCR assay can be used for single nematodes. The detection of other undescribed Anguina species should also be possible by the Anguina genus-specific primers included in this assay. This assay can be used for screening Anguina tritici morphological suspect samples.

Anguina tritici is closely related to Anguina funesta and Subanguina wevelli. The morphological separation of these three species is difficult (SON, n.d.). Recent molecular diagnostic techniques have facilitated the separation of these three species (Powers et al., 2001).

Galls caused by A. tritici may be confused with symptoms of bunt disease caused by the fungal pathogens Tilletia indica (karnal bunt) (EPPO, n.d.), T. laevis / T. tritici (stinking/common bunt) (Burrows, n.d.; Bridge and Starr, 2007). In addition, there are many other pathogens of wheat which are present in fields and in seed lots (Asaad and Abang, 2009), and some plant disease galls resemble nematode galls and may erroneously indicate the presence of A. tritici (CABI, 2015

Powers et al. (2001) described the PCR-RFLP patterns of the internal transcribed spacer region (ITS1) of A. tritici and several other species of Anguina . In the study, the restriction enzymes Alu I, Hha I, and Hinf I, used individually, were able to differentiate A. tritici from other Anguina species. These patterns were different between Anguina spp. and allows for the possibility of molecular diagnosis of A. tritici .

This nematode was first identified in the United States in 1909, and it spread to numerous states, where it was primarily associated with wheat but also with rye to a lesser extent. Modern agricultural practices, including use of clean seed and crop rotation, have all but eliminated A. tritici in Western countries, and the nematode has not been found in the United States since 1975.