Rev 09/13/2023
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Tylenchina
Tylenchoidea
Pratylenchidae
Pratylenchinae
Hirschmanniella Luc and Goodey, 1964
Type species of the genus: Hirschmanniella oryzae (van Breda de Haan, 1902) Luc& Goodey, 1964
Synonyms:
Hirschmannia Luc and Goodey, 1962
Classified in the Pratylenchinae because of the long ventral overlap and lack of sexual dimorphism.
Nematode is 0.9-4.2 mm long, is slender, amphidelphic.
Deirids absent.
Lip area flattened anteriorly to hemispherical, not set-off. Lip sectors and labial disc often fused.
Labial sclerotization strong.
.
Esophageal glands in line, with a long ventral overlap of the intestine.
[Ref: Luc, (1987) and H. Ferris]
Tail length three or more times anal body diameter, usually terminating in a point or mucro.
Phasmids generally situated in posterior third of the tail.
A Polytomous Key to species of the genus Hirschmanniella
(adapted from Kuhn et al (2015).
Definition of Characters in the Key:
Character A Lip region 1) Hemispherical; 2) Not hemispherical
Character B Tail terminus shape. 1) Pointed or round terminus with a mucro, 2) Pointed terminus with subterminal notch , 3) Pointed or round terminus with or without a projection
Character C Number of mucro or projection. 1) No or single mucro or projection; 2) Two or more mucros or projections.
Character D Position of mucro or projection. 1) Axial position 2) Ventral position
Character E Position SE pore with respect to the PIJ. 1) SE pore anterior to PIJ; 2) SE pore about same level as PIJ; 3) SE pore posterior to PIJ.
Character F Stylet length. 1) Stylet = 18.5 μm or shorter; 2) Stylet = 18.6-25.0 μm; 3) Stylet = 25.1-32.0 μm; 4) Stylet = 32.1-39.9 μm; 5) Stylet = 40 μm or longer.
Character G Body length. 1) L = 1600 μm or shorter; 2) L = 1601- 2500 μm; 3) L = 2501-3000 μm; 4) L = 3001 μm or longer.
Character H Ratio c . 1) c = 3.0 or lower; 2) c = 3.1-4.9; 3) c = 5.0-6.9; 4) c = 7.0-8.9; 5) c = 9.0 or higher.
Character I The number of ventral annules from phasmids to tail terminus. 1) 14 annules or lower; 2) 15-24 annules; 3) 25- 34 annules; 4) 35 annules or higher.
Character J Spicule length. 1) 27 μm or shorter; 2) 28-40 μm; 3) 41 μm or longer.
Character K Geographical distribution. 1) Europe; 2) Africa; 3) North America; 4) South and Central America, including the Caribbean; 5) Asia; 6) Oceania. B
Interpretation of character states F-J: the first digit represents the reported mean value, the second represents the minimum value and the third represents the maximum value.
Interpretation of character states E and K: the first digit represents the most frequent state of the character and the other digits represent alternative states of the charaxcter in decreasing frequency.
Character states that are rare exceptions are indicated in parentheses; superscripts a and b indicate characters derived from drawings in the original description or from voucher specimens.
Polytomous Key is from Kuhn et al (2015).
Generally, the species of this genus are associated with grassy plants growing in wet or aquatic conditions, e.g., rice, reeds, sedges.Lake bottom (reeds). Locally the genus is reported from several locations, including reeds near Tulelake, reeds along ditches in Yolo County, paddy rice, Santa Ana River (southern California).
In Europe, five Hirschmanniella species were reported: as of 2010: H. gracilis (Sweden, Denmark, Germany, the Netherlands, Belgium, Austria, Romania, Russia, Poland, H. loofi (the Netherlands, Belgium, Poland, Germany, H. oryzae (Georgia) and H. behningi (Russia: Volga river basin, Poland, Sweden: ), and H. zostericola (Sweden) (Ryss and Karnkowski, 2010).
Nematodes of the genus Hirschmanniella differ significantly in their morphological features and habitat from other plant‐parasitic nematodes. They are parasites of roots, stems and leaves of water‐inhabiting vascular plants and the roots of higher plants growing in temporarily flooded and swampy soils. Some species are pathogenic to rice and sugar cane in subtropical and tropical regions.
D-rated pest in California Nematode Pest Rating System, except for H. oryzae, which is A-rated.
The genus Hirschmanniella is considered one of the most important nematode pests of rice. Several species cause serious economic problems in lowland rice in Southeast Asia ( Bridge et al., 1990; Prot et al., 1994; Karssen, 2009; Maung et al., 2010; Win et al., 2013).
Hirschmanniella oryzae reduced tiller growth by 50-60% in transplanted rice seedlings and reduced yield by >25% (Ou, 1985; Jairajpuri & Baqri, 1991).
More than half of the known Hirschmanniella species have been reported as pests of rice while several other species are reported from other crops, including taro (Bridge et al., 1983), cabbage (Duan et al., 1996), maize, tomato and sugarcane (Bridge et al., 1990).
Some Hirschmanniella species have been recorded from marine environments as parasites of aquatic plants including Diplanthera wrightii (Sher, 1968) and Ceratophyllum demersum (Gerber & Smart, 1987).
Most species of Hirscmanniella are quarantine pests for the European Union (Khun et al., 2015). With the exception of H. gracilis (De Man, 1880) which occurs widely in Europe, nematodes of the genus Hirschmanniella,have been recognized as EU quarantine pests . Additionally, H. oryzae is a quarantine pest of the Caribbean Plant Protection Commission and of Brazil, whilst H. spinicaudata is recognized as a quarantine pest of the Asia and Pacific Plant Protection Commission (Ryss and Karnkowski, 2010).
Rice, reeds, common cattail (Typha latifolia).
Sexually reproducing, sex ratio is about 1:1.
Bridge, J., Mortimer, J.J. & Jackson, G.V.H. (1983). Hirschmanniella miticausa n. sp. (Nematoda: Pratylenchidae) and its pathogenicity on taro (Colocasia esculenta). Revue de N�matologie 6, 285-290
Bridge, J., Luc, M. & Plowright, R.A. (1990). Nematode parasites of rice. In: Luc, M., Sikora, R.A. & Bridge, J. (Eds). Plant parasitic nematodes in subtropical and tropical agriculture. Wallingford, UK, CAB International, pp. 69- 108.
Duan, Y., Liu, W., Liu, Y. & Zhao, H. (1996). A new species of Hirschmanniella (Pratylenchidae) associated with the Brassicae (Brassica oleracea var. capitata). Journal of Shenyang Agricultural University 3, 35-38.
Gerber, K. & Smart, G.C. (1987). Effect of Hirschmanniella caudacrena on the submersed aquatic plants Ceratophyllum demersum and Hydrilla verticillata. Journal of Nematology 19, 447-453..
Jairajpuri, M.S. & Baqri, Q.H. (1991). Nematode pests of rice. New Delhi, India, Oxford & IBH Publishing.
Karssen, G. (2009). Hirschmanniella spp. EPPO Bulletin 39, 369-375.
Khun, K., Decraemer, W., Couvreur, M., Karssen, G., Steel, H., Bert, W. 2015. Deceptive morphological variation in Hirschmanniella mucronata (Nematoda: Pratylenchidae) and a polytomous key to the genus. Nematology 17: 377-400.
Luc, M. & Goodey, J.B. (1962). Hirschmannia n. g. differentiated from Radopholus Thorne, 1949 (Nematoda: Tylenchoidea). Nematologica 7, 197-202.
Luc, M. & Goodey, J.B. (1964). Hirschmanniella nom. nov. for Hirschmannia. Nematologica 9(1963), 471-471.
Luc, Rev. Nematol. 10(2):203-218 (1987)
Maung, Z.T.Z., Kyi, P.P., Myint, Y.Y., Lwin, T. & De Waele, D. (2010). Occurrence of the rice root nematode Hirschmanniella oryzae on monsoon rice in Myanmar. Tropical Plant Pathology 35, 3-10.
Ou, S.H. (1985). Diseases caused by nematodes. In: Ou, S.H. (Ed.). Rice diseases, 2nd edition. Wallingford, UK, CABI Publishing, pp. 337-364.
Prejs, K. 1986. Occurrence of stylet-bearing nematodes associated with aquatic vascular plants. Ekologia Polsaka 34:185-192.
Prot, J.C., Soriano, I.R.S. & Matias, D.M. (1994). Major rootparasitic nematodes associated with irrigated rice in the Philippines. Fundamental and Applied Nematology 17, 75- 78.
Photomicrographs by H. Ferris and John Chitambar, CDFA
Ryss, A.Y. and Karnkowski, W. 2010. Hirschmanniella caudacrena Sher (1968) intercepted in aquarium plants imported to Poland. EPPO Bulletin 40:204-210.
Sher, S.A. (1968). Revision of the genus Hirschmanniella Luc & Goodey 1963 (Nematoda: Tylenchoidea). Nematologica 14, 243-275.
Win, P.P., Kyi, P.P., Maung, Z.T.Z. & De Waele, D. (2013). Population dynamics of Meloidogyne graminicola and Hirschmanniella oryzae in a double rice-cropping sequence in the lowlands of Myanmar. Nematology 15, 795-807.