Mesocriconema sphaerocephala

Zeng, Yongsan, Ye, Weimin, Tredway, Lane, Martin, Samuel & Martin, Matt, 2012, Taxonomy and morphology of plant-parasitic nematodes associated with turfgrasses in North and South Carolina, USA, Zootaxa 3452, pp. 1-46 : 25

Mesocriconema sphaerocephala

( Fig. 5 C, H, I)

Measurements. See Tables 11 .

Remarks. Mesocriconema sphaerocephala was first described from soil around the roots of a grass on Trinidad by Taylor (1936). It has been found with centipedegrass ( Eremochloa ophiuroides ) in Florida ( Tarjan 1964b; Tarjan & Frederick 1981), bermudagrass in India ( Siddiqi 1961), grasslands in Spain ( Escuer et al. 1999), and other plants in many countries. In the present study, M. sphaerocephala was found in Montgomery County, NC, and Beaufort County, SC. It occurred mainly in the warm-season (C4) grasses (bermudagrass and zoysiagrass), but not in the cool-season (C3) grasses such as creeping bentgrass. The morphology and morphometrics fit the description of previously described populations ( Orton Williams 1973b). This is the first record of M. sphaerocephala from turfgrasses in NC and SC.

Diagnosis of three Mesocriconema species from turfgrasses

Ring nematodes are the most common species encountered in golf courses and occur at fairly high densities, but species identification is challenging. The three ring nematodes identified above ( M. xenoplax , M. curvatum and M. sphaerocephala ) are similar in general morphology. They can be distinguished from each other using the characteristics listed in Table 12 . Mesocriconema sphaerocephala is the shortest of these species, lacks labial plates, and has the least body annulations with posterior margins and anastomoses, hemispherical head and bluntly rounded or hemispherical tail. Mesocriconema xenoplax is the longest of the three species and has rounded, retrorse body annulations that may be smooth or slightly rough, a broad head and four distinct and well-separated labial plates, a sigmoid vagina and broadly rounded to more conoid tail. Mesocriconema curvatum has smooth body annulations without posterior margins and anastomoses, more or less rectangular labial disc with slit-like apertures along its lateral margins, a distinctly lower labial disc than M. xenoplax and a conoid-rounded tail, head not offset and vagina not sigmoid.

Figures

FIGURE 5. Micrographs of Mesocriconema curvatum, M. xenoplax, M. sphaerocephala and Ogma floridense from turfgrasses in NC and SC. All scale bars = 20 µm. A. Pharyngeal region of M. curvatum. B. Pharyngeal region of M. xenoplax. C. Pharyngeal region of M. sphaerocephala. D, G. Female tail of M. xenoplax. E. Pharyngeal region of O. floridense. F. Female tail of M. curvatum. H. Female tail of M. sphaerocephala. I. Body with anastomoses of M. sphaerocephala. J. Vulva and tail region of O. floridense.