Journal of Nematology 25(3):344-348. 1993. © The Society of Nematologists 1993. Distribution of Xiphinema americanum and Related Species in North America 1 R. T. ROBBINS 2 Abstract: All species of the Xiphinema americanum-group and their synonyms are listed. The North American species reported are listed by state or province. Among these species, X. rivesi has the most widely reported distribution. Six species (X. diffusum, X. floridae, X. laevistriatum, X. luci, X. shell, and X. tarjanense) have been reported from only Florida. The reports of X. pachtaicum, X. sheri, and X. luci did not include morphometrics and need to be confirmed; X. brevicolle from California was identified before Lamberti and Bleve-Zacheo described 15 new species in 1979 and similarly needs to be confirmed. Because of the proliferation of species in this group, reports of X. americanum (sensu stricto) before 1979 are questionable. Extraction techniques for longidorids are discussed. Key words: distribution, extraction, nematode, North America, Xiphinema americanum. In a symposium at the Second Interna- and Luc (15), plus the three new species tional Nematology Conference in 1990, I described by Lamberti et al. (11). Loof and presented information on the distribution Luc (15) considered five other species to be of the North American Longidoridae very close to the X. americanum group but (Longidorus, Paralongidorus, and Xiphinema) did not include them for various reasons (20). Later, I and D.J.F. Brown summa- (Table 2). rized the taxonomy and distribution of the The 20 species of the X. americanum nepovirus-vectoring Longidoridae of group reported from North America (Ta- North America (21). The Xiphinema ameri- ble 3) and their distribution was compiled canum-group species were included in both by Robbins and Brown (21). Xiphinema reports (20,21). americanum Cobb, 1913 (sensu stricto) is In 1990, Loof and Luc published a poly- probably more widespread than indicated tomous key to the species of Xiphinema in Table 3, which includes only the loca- Cobb, 1913 that they considered to be tions reported in redescriptions or from valid, including species synonyms (15). In personal identifications (12,21,23). Be- their key, the 32 species of the X. america- cause of the proliferation of species in the num-group were not differentiated from X. americanum group since 1979, identifica- each other because they had similar char- tions of X. americanum before this time are acter codes. These codes refer to a variety questionable. of morphological characteristics. In 1991 Distribution of the members of the X. Lamberti and Carone (10) recognized 38 araericanum group varies greatly. Xiphinema species of the X. americanum group and rivesi Dalmasso, 1969 has the widest re- published a dichotomous key, along with ported North American distribution (4,9, tail shape drawings. No head shapes or 19,21,25,27). It has been reported from morphometrics were included with this the Atlantic coast to the Rocky Mountains. key which, I believe, limits its utility. The Xiphinema brevicolle Lordello & da Costa, current worldwide list (Table 1) of the X. 1961, first described from South America, americanum-group species and their syn- is reported in California, Nevada, and onyms includes those reported by Loof Utah (13,21,24). In 1991, Lamberti et al. (11) redescribed X. brevicolle and differen- tiated it from X. diffusum Lamberti & Received for publication 26 October 1992. Bleve-Zacheo, 1979. The California popu- t Published with the approval of the director of the Arkan- lation was reported in 1973 and needs to sas Agricultural Experiment Station. Symposium paper pre- sented at the 31st Annual Meeting of the Society of Nema- be confirmed, i recently examined fixed tologis's, 2-6 August 1992, Vancouver, British Columbia, California X. brevicolIe specimens, found Canada. 2 Professor, Department of Plant Pathology, Nematology four juvenile stages to occur, and pre- Laboratory, University of Arkansas, Fayetteville, AR 72701. sented this finding and the supporting 344 Xiphinema americanum in North America: Robbins 345 data at the 21 st International Nematology TABLE 1. A list of valid species and synonyms of Symposium of the European Society of the Xiphinema americanum group (10,15). Nematologists in April 1992. The presence of four juvenile stages suggests that X. X. americanum Cobb, 1913 (type species) brevicoUe may be an imported species, as = Tylencholaimus americanus (Cobb, 1913) Micoletzky, 1922 most of the North American species stud- X. brevicoUe Lordello & da Costa, 1961 ied have three juvenile stages. The report Syn. X. americanum apud Carvalho (1955, 1962) from Nevada and Utah was made before Syn. X. saopaoloense Khan & Ahmad, 1975 the redescription of Lamberti et al. (11) X. bricolense Ebsary, Vrain & Graham, 1989 X. californicum Lamberti & Bleve-Zacheo, 1979 but was not mentioned therein. X. citricolum Lamberti & Bleve-Zacheo, 1979 Xiphinema bricolense Ebsary, Vrain & Gra- X. diffusum Lamberti & Bleve-Zacheo, 1979 ham, 1989 has been found in sites near the X. floridae Lamberti & Bleve-Zacheo, 1979 Pacific coast of British Columbia and Cal- X. fortuitum Roca, Lamberti & Agostinelli, 1988 X. georgianum Lamberti & Bleve-Zacheo, 1979 ifornia (2,5,21). Xiphinema californicum X. inaequale Khan & Ahmad, 1977 Lamberti & Bleve-Zacheo, 1979 has been Syn. X. neoamericanum Khan & Ahmad, 1975 reported the from the widely separated Homonym of X. neoamericanum Saxena, Chabbra states of Arkansas, California, New York, & Joshi, 1971 X. incertum Lamberti, Choleva & Agostinelli, 1983 Pennsylvania, and Guanguato (Mexico) (6, X. incognitum Lamberti & Bleve-Zacheo, 1979 8,9,13,26). Originally described from X. intermedium Lamberti & Bleve-Zacheo, 1979 three females and one male from Florida, X. kosaigude~zse Quraishi & Das, 1984 X. laevistriatum Lamberti & Bleve-Zacheo, 1979 X. citricolum Lamberti & Bleve-Zacheo, X. lambertii Bajaj & Jairajpuri, 1977 1979 has also been reported from Arkan- x. luci Lamberti & Bleve-Zacheo, 1979 sas (2,9). Xiphinema pachtaicum (Tulaganov, X. occiduum Ebsary, Potter & Allen, 1984 1938) Kirjanova, 1951 was reported from X. opistohysterum Siddiqi, 1961 X. oxycaudatum Lamberti & Bleve-Zacheo, 1979 California and Oregon and is thought to X. pachtaicum (Tulaganov, 1938)Kirjanova, 1951 have been introduced with planting mate- = Longidorus pachtaicum Tulaganov, 1938 rial, probably grapevines from Europe Syn. X. medite~'raneum Martelli & Lamberti, 1967 (14,22). Because morphologic data was not Syn. X. neoelongatum Bajaj & Jairajpuri, 19777 x. pachydermum Sturhan, 19835 presented, this species identification needs X. pac~cum Ebsary, Vrain & Graham, 1989 to be confirmed. X. paramonovi Romanenko, 1981 Six X. americanum-group species de- Syn. X. paramericanum Romanenko, 1973 scribed by Lamberti and Bleve-Zacheo in X. parvum Lamberti, Ciancio, Agostinelli & Coiro, 1991 1979 (X. diffusum, X. floridae, X. laevistria- X. peruvianum Lamberti & Bleve-Zacheo, 1979 tum, X. luci, X. sheri, and X. tarjanense) have X. pseudoguirani Lamberti, Ciancio, Agostinelli & been reported from Florida only (9,17,18, Coiro, 1991 21). For X. luci and X. sheri, described from Syn. X. guirani apud Lamberti & Bleve-Zacheo, 1979 Senegal and Thailand respectively, no X. rivesi Dalmasso, 1969 morphometric data were given; thus, the X. sheri Lamberti & Bleve-Zacheo, 1979 species identifications need to be con- X. silvaticum Luc & Williams, 1978 X. simile Lamberti, Choleva & Agostinelli, 1983 firmed (17,18,21). The only North Amer- X. tarjanense Lamberti & Bleve-Zacheo, 1979 ican population of X. diffusum (from Key X. taylori Lamberti, Ciancio, Agostinelli & Coiro, West, Florida) appears to be close to X. par- 1991 vum Lamberti, Ciancio, Agostinelli, & X. tenuicutis Lamberti & Bleve-Zacheo, 1979 X. thornei Lamberti & Golden, 1986 Coiro, 1991, which is from Jamaica. A sev- X. utahense Lamberti & Bleve-Zacheo, 1979 enth species, Xiphinema neoelongatus Sax- Species inquirenda ena, Chabbra, & Joshi, 1973, was reported t Xiphinema neoamericanum apud Saxena, Chabbra & Joshi, by Norton et al. from Florida (19). Because 1973, a valid species according to Lamberti & Carone (10) is this report was a personal communication regarded as a species inquirenda (15,16). :~ Included in the X. americanum group by Lamberfi & Ca- without any morphometrics, the status of rone (10). this species needs confirmation. This spe- cies is considered valid by Lamberti & Ca- 346 Journal of Nematology, Volume 25, No. 3, September 1993 TABLE 2. A list of Xiphinema species very close to the X. americanum-group and the differences separating them from it (15). Species and authority Differences described X. elitum Khan, Chawla & Saha, 1978 Peculiar tail shape, much longer tail length. X. elongatum Schuurmans Stekhoven & Vulva position 30-44%, exceptionally 45-49%, tail Teunissen, 1938 much longer than X. americanum-group. Syn. X. campinense Lordello, 1951 Syn. X. hydrabadense Quraishi & Das, 1984 Syn. X. nagarjunense Khan, 1982 Syn. X. pratense Loos, 1949 Syn. X. usai Edward & Sharma, 1982 X. louisi Heyns, 1979 Longer body length, longer hyaline portion of tail. X. mampara Heyns, 1979 Longer body length, longer hyaline portion of tail, males common. X. pachydermum Sturhan, 1983~ Long uteri, many males. X. variable Heyns, 1966 Body generally more slender, males common. ? Included in the X. americanura group by Lamberti and Carone (10). rone (10) but species inquirenda by Loof & Canadian provinces of Alberta, Manitoba, Luc (15) and Luc et al.