Body annulated, pearly white, globular to pear-shaped, with slight posterior protuberance and distinct neck region projecting from the body axis up at an angle of 90 degrees to one side. Head region set off from body, marked with one of two annules. Head cap distinct but variable in shape; labial disc slightly elevated. Cephalic framework weakly sclerotized; vestibule extension distinct.
Stylet cone dorsally curved and shaft cylindrical; knobs large, rounded to transversely ovoid; slightly sloping posteriorly from the shaft. Excretory pore located between head end and metacorpus levels. One or two large vesicle-like structures, and several smaller ones located along the lumen lining. Pharyngeal glands variable in size and shape.
Perineal pattern ovoid to oval shaped, sometimes rectangular; dorsal arch ranging from low to moderately high, with coarse striae. Tail terminus indistinct without punctations. Phasmids small and difficult to observe. Perivulval area devoid of striae. Lateral lines indistinct (LM), appearing as a weak indentation under SEM, increasing towards the tail terminus region and resulting in a relatively large area without striae. Ventral pattern region oval to angular shaped; striae moderately coarse.
Body vermiform, slightly tapering anteriorly, bluntly rounded posteriorly. Cuticle with distinct transverse striae. Lateral field with four incisures; outer ones irregularly aerolated; a fifth broken longitudinal incisure is rarely present near mid-body.
Head slightly set off, with a single post-labial annule (sometimes called head region) usually partly subdivided with a transverse incisure. Labial disc rounded, elevated and fused with medial lips. Prestoma hexagonal in shape with six inner cephalic sensilla adjacent to the rim. Medial lips crescent shaped with raised edges at lateral sides. Four cephalic sensilla small and marked by cuticular depressions on the medial lips. Amphidial openings appear as elongated slits between labial disc and medium sized lateral lips. Cephalic framework moderately sclerotized, vestibule extension distinct.
Stylet cone straight; shaft cylindrical; knobs large and rounded, set off from the shaft. Pharynx with slender procorpus, metacorpus oval shaped with pronounced valve. Ventrally overlapping pharyngeal gland lobe variable in length. Hemizonid, 2-3 um in length, two to four annules anterior to excretory pore.
Testis usually long, monorchic, with reflexed or outstretched germinal zone. Tail short and twisted. Spicules slender, curved ventrally; gubernaculum slightly crescent shaped. Phasmids located anterior to cloaca.
Body moderately long, veriform, tapering at both ends but posteriorly more than anteriorly. Body annules small but distinct. Lateral field with four incisures, not areolated. Head region truncate, slightly set off from body. Head cap low and narrower than head region. Cephalic framework weakly sclerotized, vestibule extension distinct.
Stylet slender and moderately long, cone straight; shaft cylindrical; knobs distinct, rounded and set off from the shaft. Pharynx with faintly outlined procorpus and oval shaped metacorpus with distinct valve. Pharyngeal gland lobe variable in length, overlapping intestine ventrally. Hemizonid distinct at the same level with the excretory pore.
Moderately sized tail, gradually tapering until hyaline tail terminus, with inflated proctodeum. Phasmids difficult to observe, small, slightly posterior to anus. A rounded hypodermis marked the anterior position of the smooth hyaline tail terminus ending in a broadly rounded tip. Terminus generally marked by faint cuticular constrictions.
Eggs (n = 30)
Length 90 - 104 um (94 + 3.4); width 34.1 - 44.2 um (38.9 + 3.2); length / width ratio 2.1 - 2.9 ( 2.4 + 0.2).
In the field detected on different economical important crops like potato and carrot, recent host tests indicate that it is able to parasitize, like M. chitwoodi, on a wide range of mono- and dicotyledonous plants. Both root-knot nematodes share hosts, but also species specific host have been found. M. fallax induces on most plants relatively small galls.
Host preference studies showed that Phaseolus vulgaris L. cv's Iprin, Strike and Groffy, Zea mays L., Potentilla fruticosa L. and Erica cinerea L. were good hosts for M. chitwoodi but not for M. fallax. On the other hand M. fallax reproduced well on Oenothera erythrosepala Borb., Phacelia tanacetifolia Bentham, Dicentra spectabilis (L.) Lem. and Hemero callis cv Rajah, while M. chitwoodi reproduced not or poorly (Brinkman et al., 1996)
Detected so far in the southern part of the Netherlands, Belgium, Germany (one location) and France (one location).
Type locality and host
Described from roots of tomato (Lycopersicon esculentum Mill.). The nematodes were originally isolated from infected roots of black salsify (Scorzonera hispanica L. ev. Lange Jan) from arable land one mile north of Baexem, province of Limburg, the Netherlands.
(Description- Karssen, 2002)
DNA Sequences Obtained