Rev 12/02/2021
Synonyms:
Reported median body size for this species (Length mm; width micrometers; weight micrograms) - Click:
Europe, Australia, Canada, U.S. (especially Pacific Northwest), New Zealand, and former Soviet Union.
Anguina agrostis is a B-rated pest in California, USA.
37, 46, and 48% of orchard grass seed samples from the Willamette Valley of Oregon during 1996, 1997, and 2000, respectively, containing Anguina galls. The number of galls ranged from 1-24 per 25 g of grass seed (Alderman et al., 2003).
Anguina agrostis was first described from bent grass (Agrostis capillaris) in Germany. Over time, a lengthy host list of additional grasses was added. An analysis of the ITS rRNA gene sequences made by Subbotin et al. (2004, 2020) showed that the host ranges of seed gall nematodes are limited and the host range of A. agrostis was limited to Agrostis capillaris. Other grasses previously indicated as hosts were parasitized by several other described and still undescribed species of Anguina. Anguina agrostis sensu stricto causes characteristic elongate galls and abnormally elongated floral structures in Agrostis grasses. A recent report on this nematode indicates a new host, blue fowl grass, Poa paulustris in Wyoming (Roubtsova and Subbotin, 2020).
Annual and perennial rye grasses and bent grasses.
The following are listed as hosts in various literature sources: to Anguina "agrostis" sensu lato.. But see above, the host list of A. agrostis sensu stricto is currently limited to Anguina capillaris and Poa palustris (Scheck, 2021).
Ecophysiological Parameters:
Similar to A. tritici, except that second stage hatches from egg.
One generation produced per year. Seed gall ruptures when mucoprotein takes up water and expels nematodes. This corresponds to favorable conditions for germination of host seeds.
Nematodes can remain viable in dry, cigar-shaped galls for up to 10 years.
Second state juveniles (J2) hatch and invade young grasses in early May in Europe or the end of August in Australia. J2s may feed as ectoparasites during the vegetative growth stage, migrating to areas of new growth or being carried up with the growing point of the plant. When the grass inflorescence begins to form, the J2s invade the flower ovule and begin to feed as endoparasites.
Maturation and oviposition begin in mid-June or mid-October, depending on the hemisphere, with only one generation per year (Pinkerton and Alderman, 1994; Riddle and Byrd, 1984; Krall, 1991).
Nematode feeding on floret primordia induces rapid cell division, cell enlargement, and subsequent cell degeneration and collapse. As this process continues, a large central cavity forms and is enveloped by a gall wall, and the nematodes reside inside. Gall size will increase rapidly as nematodes grow and reproduce. The gall wall is several cell layers thick with inner cells of the gall wall with dense cytoplasm with several mitochondria, and high levels of metabolic activity. These cells provide nutrients to the nematodes. Within the gall, nematodes go through three molts, J3, J4, and a final molt to become either male or female adults.
Reproduction is amphimictic and females can lay up to 1000 eggs. The first molt occurs in the egg and the nematode hatches as a J2. These juveniles undergo anhydrobiosis and become the dormant dauer stage to withstand the summer heat. Winter or spring rains cause the seed galls to rupture when their mucoprotein takes up water and expels nematodes. This corresponds to favorable conditions for germination of host seeds. As the plant senesces, the galls desiccate, and the nematodes undergo anhydrobiosis, a state that can last for many years (Subbotin and Riley, 2012).
In Australia, a bacterium formerly considered to be Corynebacterium rathayi attaches to nematode cuticle and is carried into seed gall. Corynebacterium rathayi is now reclassified as Clavibacter rathayi and the ryegrass toxicity organism is considered closely related to but may be a new species of Clavibacter (Riley, 1987).
The bacterium outcompetes the nematode for resources in seed gall, increases, and coats surface which becomes sticky and yellow; produces a neurotoxin that causes convulsion and mortality in grazing animals, i.e., "Staggers." - term used for the effect on sheep[ in Australia. The toxin is produced late in season as the gall matures ( Bird and Stynes, 1977).
Livestock poisoning is occasionally reported in the U.S., otherwise, majority of the damage caused by the nematode results in reduction of seed yield.
The relationship between nematode and bacterium is similar to that between A. tritici and Clavibacter tritici that causes Tundu disease of wheat.
Anguina agrostis is a serious and important nematode pest of bent grass grown for seed, especially in the Pacific Northwest of the United States and New Zealand (Pinkerton and Alderman, 1994; Southey, 1973). Hosts: Agrostis capillaris (colonial bent grass), Poa palustris (fowl bluegrass) (Roubtsova and Subbotin, 2020). Colonial bent grass and fowl bluegrass are both non-native perennials. They are widespread in California, especially along the coast and in the Sierra Nevada (Calfora, 2021).
Detection:
In grasses, seed galls are difficult to detect as they are covered by lemmas and paleas. A small scarifier can be used to remove lemmas and paleas without damage to seeds or galls. That allows visual identification of galls (Alderman et al., 2003).
Management:
Ryegrass toxicity:
Host Plant Resistance, Non-hosts and Crop Rotation alternatives:
Avoidance:
Galls containing nematodes can be harvested and shipped with seeds. The galls can be difficult to detect as they are covered by the chaffy scales or bractlets around the florets. Mechanical seed cleaning removes most galls, but control is more effective when combined with hot water treatment.
Movement with sand, soil or water is also possible (CABI-ISC, 2021).
Alderman SC, Bilsland DM, Griesbach JA, Milbrath GM, Schaad NW, Postnikova E. 2003. Use of a seed scarifier for detection and enumeration of galls of Anguina and Rathayibacter species in orchard grass seed. Plant Disease 87:320-323.
Bird, A.F., Stynes, B.A. 1977. The morphology of a Corynebacterium sp. parasitic on annual ryegrass Phytopathology 67:828-830.
CABI Invasive Species Compendium 2021. Anguina agrostis. https://www.cabi.org/cpc/datasheet/120026 Accessed 8/9/21
Chitambar, J. J., Westerdahl, B. B., and Subbotin, S. A. 2018. Plant Parasitic Nematodes in California Agriculture. In Subbotin, S., Chitambar J., (eds) Plant Parasitic Nematodes in Sustainable Agriculture of North America. Sustainability in Plant and Crop Protection. Springer, Cham.
Chizhov, V. N., and Subbotin, S. A. 1990. [Plant-parasitic nematodes of the subfamily Anguininae (Nematoda, Tylenchida). Morphology, trophic specialization, system.] Zool. Zh. 69:15-26 (in Russian).
CIH Descriptions of Plant-parasitic Nematodes, Set 2, No. 20 (1973)
EPPO Global Database. 2021. Anguina agrostis https://www.cabi.org/isc/datasheet/5386 Accessed 10/25/21
Evtushenko, L.I., Dorofeeva, L.V., Dobrovolskaya, T.G. and Subbotin, S.A., 1994. Coryneform bacteria from plant galls induced by nematodes of the subfamily Anguininae. Russ J Nematol, 2, pp.99-104.
Evtushenko, Lyudmila I., Lubov V. Dorofeeva, Tatyana G. Dobrovolskaya, Galina M. Streshinskaya, Sergey A. Subbotin, and James M. Tiedje. "Agreia bicolorata gen. nov., sp. nov., to accommodate actinobacteria isolated from narrow reed grass infected by the nematode Heteroanguina graminophila." International journal of systematic and evolutionary microbiology 51, no. 6 (2001): 2073-2079.
Goodey, J. B., M. T. Franklin, and D. J. Hooper. 1965. T. Goodey's: The Nematode Parasites of Plants Catalogued Under Their Hosts. Commonwealth Agricultural Bureaux, Farnham Royal, Bucks, England. Third Edition
Hooper, D.J. and Southey, J.F. 1978. Ditylenchus, Anguina and related genera. In: Southey, J.F. (Ed.). Plant nematology. London, UK, HMSO, pp. 78-97.
Jensen, H. J. 1961. Nematodes Affecting Oregon Agriculture. Oregon State University, Corvallis.
Krall, E.L. 1991. Wheat and Grass Nematodes: Anguina, Subanguina, and Related Genera. Pages 721-760 in: Manual of Agricultural Nematology, W. Nickle, ed. CRC Press, New York, NY.
Kurochkina, K. G., and Chizhov, V. N. 1980. [On the toxicity of Anguina agrostis galls to animals]. IX Konferentsiya Ukrainskogo Parazitologicheskogo Obshchestva. Tezisy dokladov. VIGIS Mosc. USSR 2:206 (In Russian).
Murray, T.D., Schroeder, B.K., Schneider, W.L., Luster, D.G., Sechler, A., Rogers, E.E. and Subbotin, S.A., 2017. Rathayibacter toxicus, other Rathayibacter species inducing bacterial head blight of grasses, and the potential for livestock poisonings. Phytopathology, 107(7), pp.804-815.
Pinkerton, J. N., and S. C. Alderman. 1994. Epidemiology of Anguina agrostis in highland colonial bentgrass. Journal of Nematology26:315-323.
Riddle, D. L., and A. F. Bird. 1985. Responses of Anguina agrostis to detergent and anesthetic treatment. Journal of Nematology 17:165-168.
Riley, 1987; International Journal of Systematic Bacteriology 35:153-159
Roubtsova, T.V. and Subbotin, S.A., 2020. First report of the bent seed gall nematode, Anguina agrostis (Steinbuch, 1799) Filipjev, 1936 from Poa palustris L. in Wyoming, USA. Journal of Nematology, 52.
Roubtsova, T.V., Burbridge, J. and Subbotin, S.A., 2020. Molecular characterisation and diagnostics of some gall-forming nematodes of the family Anguinidae Nicoll, 1935 (Nematoda: Tylenchida) using COI mtDNA. Russian Journal of Nematology, 28(2).
Scheck, H.J. 2021. California Pest Rating Proposal for Anguina agrostis (Steinbuch, 1799) Filipjev, 1936 Bent grass seed gall nematode. CDFA, Sacramento.
Siddiqui, I. A., S. A. Sher and A. M. French. 1973. Distribution of Plant Parasitic Nematodes in California. State of California Department of Food and Agriculture, Division of Plant Industry. 324p.
Southey, J.F., 1973. Anguina agrostis. CIH Descriptions of Plant-parasitic Nematodes Set, 2(20), p.3.
Stynes, B. A. and A. F. Bird. 1980. Anguina agrostis, the vector of annual rye grass toxicity in Australia. Nematologica 26:475-490.
Subbotin, S. A., and I. T. Riley. 2012. Stem and gall nematodes. In Practical Plant Nematology (book) Edited by R. H. Manzanilla-Lopez and N. Marb�n-Mendoza. Biblioteca Basica de Agricultura, p. 521-577.