MELOIDOGYNE ORYZAE

IDENTITY: Scientific name: Meloidogyne oryzae
Maas, Sanders & Dede, 1978
 Common name: A root-knot nematode

NOTES ON TAXONOMY AND BIOLOGY: Female M. oryzae have an oval cuticular perineal pattern similar to that of M. arenaria. It has a moderately high dorsal arch and lacks prominent lateral lines. A thick fold is present in the area below the anus and appears like a prominent regular line. It has sedentary endoparasitic habits. Second-stage juveniles (J2) in the soil penetrate host roots where they establish a specialized feeding site (giant cells) in the stele. As J2 develop, they cause root swellings and become swollen females. Females rupture root cortex and some time protrude with the egg masses from the root surface. J2 emerge from the egg masses and migrate in the soil. This nematode can survive flooding conditions (Bridge et al., 1990; Maas et al., 1978).

GEOGRAPHICAL DISTRIBUTION: This root-knot nematode is a tropical or subtropical species reported only in Surinam (Bridge et al., 1990).

HOSTS: Under field conditions, this root-knot nematode is a pest of rice (Oryza sativa) infecting also fimbristylis-grass (Fimbristylis miliacea). Reproduction of this nematode has been observed in greenhouse host test on, plantain (Musa sp.), potato (Solanum tuberosum), tomato (Lycopersicon esculentum), sorghum (Sorghum bicolor) and wheat (Triticum sp.) (Maas et al., 1978). Other hosts include grasses (Echinochloa colonum and E. cruspavonis, Eleocharis sp. and Hymenachne amplexicaulis) (Maas et al., 1978; Segeren and Sanchit, 1984).

CROP LOSSES: Decline and stunting of rice is reported in areas infested with this pest. No quantification of nematode damage has been published.

MEANS OF MOVEMENT AND DISPERSAL: Through root material, soil debris and infected bare root propagative plant material.

RATING: (VL) Taking into consideration the distribution of this nematode and the low chances of its introduction into the US, the risk posed by this root-knot nematode to the United States is rated very low.

REFERENCES:
    Bridges, J., M. LUC, and A. Plowright.1990. Nematode parasites of rice. Pp. 69-108 in M. Luc, R. A. Sikora, and J. Bridge eds. Plant parasitic nematodes in tropical and subtropical agriculture.  Wallingford, UK: CAB International.
    Maas, P. W. TH., H. Sanders, and J. Dede. 1978. Meloidogyne oryzae n. sp. (Nematoda, Meloidogynidae) infesting irrigated rice in Surinam (South America). Nematologica 24:305-311.
    Segeren H. A., and M. L. Sanchit. 1984. Observations on Meloidogyne oryzae Maas, Sanders & Dede, 1978 in irrigated rice in Surinam. Surinaamse Landbow 32:51-59.