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NOTES ON TAXONOMY AND BIOLOGY: This species is characterized by a well-defined accessory bulb and a well-pronounced post-uterine sac that extends for more than 50% of the distance between vulva and anus. A. funesta was considered a junior synonym of A. agrostis (Steinbuch, 1799) Filipjev 1939 (Stynes and Bird, 1980). However, in spite of their morphological affinities, these two species can be differentiated by molecular analyses (Riley et. al., 1988) A. funesta second-stage juveniles (J2) emerge from the seed galls in the soil and crawl on the new germinated ryegrass seedlings. J2 become located between young leaves and penetrate flower buds at the time of flower bud initiation. J2 stimulate gall formation in place of seeds. Juvenile development is completed in the galls. Newly formed females deposit eggs, which hatch producing J2, which remain, encased in the galls and perpetuate the plant infection in following years. Dried galls are harvested with seeds. This species is associated with a yellow slime bacterium, Rathayibacter toxicus (formerly Clavibacter toxicus and Corynebacterium toxicus), which J2 can acquire from the soil or infected plants. The bacterium is introduced in the plant tissue during seed gall formation. Such galls are fatally toxic to grazing livestock.
GEOGRAPHICAL DISTRIBUTION: This nematode has been reported only in Australia.
HOSTS: The principal host of A. funesta is annual ryegrass (Lolium rigidum).
CROP LOSSES: The association of this nematode with the toxic yellow slime bacterium causes severe losses in the livestock industry of Australia. Rangeland infested by the nematode and bacterium is unusable for grazing. The accidental introduction of this nematode would have devastating repercussions on the grain export to domestic and international markets because of the quarantines imposed against this pest by many countries.
MEANS OF MOVEMENT AND DISPERSAL: Through the characteristic dark seed galls harboring the nematode juveniles in harvested grains.
RATING: (H) The nematode is a serious damaging pest to the livestock industry, pastures, and rangeland and land for recreational uses. It is also of major regulatory significance. A complete pest risk assessment should be prepared for this nematode.
REFERENCES:
Cook, R. and G. W. Yeates. 1993. Nematode pests
of grassland and forage crops. Pp. 305-350 in K. Evans, D. L. Trudgill,
and J.M. Webster eds. Wallingford, UK: CAB International.
Powers, T.O., A. L. Szalanski, P. G. Mullin, T.
S. Harris, T. Bertozzi, and J. A. Griesbach. 2001. Identification of seed
gall nematodes of agronomic and regulatory concern with PCR-RFLP of ITS1.
Journal of Nematology 33:191-194.
Price, P. C., J. M. Fisher, and A. Kerr. 1979. On
Anguina
funesta n. sp. and its association with Corynebacterium sp.
in infecting
Lolium rigidum. Nematologica 25;76-85.
Riley, I.T., T. B. Reardon, and A. C. McKay. 1988.
Electrophoresis resolution of species boundries in seed-gall nematodes,
Anguina
spp. (Nematoda: Anguinidae), from some graminaceous hosts in Australia
and New Zealand. Nematologica 34:401-411.
Stynes, B. A., and A. F. Bird. 1980. Anguina
agrostis, the vector of annual ryegrass toxicity in Australia. Nematologica
26:475-490.