Meloidogyne incognita ( Kofoid & White, 1919 ) Chitwood, 1949

Rashidifard, Milad, Fourie, Hendrika, Daneel, Mieke Stefanie & Marais, Mariette, 2019, Morphological and morphometrical identification of Meloidogyne populations from various crop production areas in South Africa with emphasis on M. enterolobii, Zootaxa 4658 (2), pp. 251-274 : 266-268

Meloidogyne incognita ( Kofoid & White, 1919) Chitwood, 1949

Figures 3 to 5, 8

Measurements: Tables 3, 4 and 8 to 9

Female (n= 88 perineal-patterns; n=5 intact females). Body pear-shaped and round in posterior part with annulated cuticle. Head aligned well with the rest of body. Stylet narrow, straight, 20–21 µm long. Stylet knobs transversely ovoid. Dorsal gland opening 3–5 µm posterior to stylet knobs. Median bulb 67–80 µm from anterior end, with oval valve ( Fig. 4 ). Oesophagus lumen lining expanded, then narrows towards median bulb lining. Neck 140–190 µm long. Perineal-pattern circular to oval shape, dorsal arch medium high to high, apex of dorsal arch broadly rounded to square, junction between lateral lines usually y-shaped. Phasmids indistinct, 1–2 µm in diameter, interphasmidial distance 19–30 µm. Rectal punctuations sparse, usually large, lateral lines indistinct or indicated by forked striae, tail terminus distinct ( Fig. 3 ). Vulval slit 20–31 µm long, anus 10–27 µm posterior to vulva ( Table 4 ).

Male (n= 25). Body vermiform, 1199–2073 µm long. Head region aligned to the body and not set off with high and round cap. Stylet 22–26 µm long, straight, knobs large, ovoid and sloping backward. Dorsal gland opening 3–6 µm posterior to stylet knobs. Lateral fields areolated from median bulb to tail. Median bulb narrow to elongated followed by narrow isthmus. Excretory pore 115–184 µm from anterior end. Tail 11–15 µm long, not annulated. Spicule arcuate, 24–34 µm long. Gubernaculum short, 6–9 µm long. Phasmids pore-like, opposite to cloaca.

Second-stage juvenile (n= 59). Body 331–427 µm long, straight to curve ventrally, narrow, tapered anteriorly and posteriorly. Head hemispherical, not set off. Stylet 11–16 µm long, cone straight. Stylet knobs large and sloping backward. Dorsal gland opening 2–5 µm posterior to stylet knobs. Median bulb enlarged with oval valve. Excre- tory pore 63–91 µm from anterior end. Tail long 35–61 µm, conical with tapered end. The hyaline tail terminus defined.

Remarks. The M. incognita population from this study compared well with other populations from South Africa ( Kleynhans 1991). Female specimens from this study, however, differed in: stylet length (20–21 µm vs 15–17 µm) and vulval slit length (20–33 µm vs 21–27 µm) from the population described by Kleynhans (1991). The current male specimens differed from that reported by Kleynhans (1991) in: shorter DGO (2–4 µm vs 3–7 µm). The J 2 specimens differed in: body length (331–427 µm vs 362–463 µm) and tail length (35–61 µm vs 49–58 µm).

Figures

FIGURE 3. Variation in the perineal-pattern morphology within and among different mature females of Meloidogyne spp. populations sampled in agri- and horticultural production areas during 2015 and 2016. A–D: Meloidogyne enterolobii; E–H: Meloidogyne javanica; I–L: Meloidogyne incognita; M: Meloidogyne hapla.

FIGURE 4. Light microscopic photos of anterior part of Meloidogyne spp. females obtained from roots of agri- and horticultural crops in South African production areas during 2015 and 2016. A, B: M. enterolobii; C, D: M. incognita; E, F: M. javanica.