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NOTES ON TAXONOMY AND BIOLOGY: D. angustus is an above ground pest of rice. It develops and reproduces in the leaf sheath and stalk, where it feeds ectoparasitically on merstematic tissues causing dark lesions, leaf distortion and seed abortion. There is no evidence of nematode penetration into the rice grains. Nematode dormant stages localize in rice stubbles and glumes, which favor the passive dissemination of this pest.
GEOGRAPHICAL DISTRIBUTION: D. angustus is present in Bangladesh, Burma, India, Indonesia, Malaysia, Myanmar, Philippines, Thailand, and Vietnam.
HOSTS: The host range of D. angustus is limited to rice species (Oryza spp.).
CROP LOSSES: Yield losses induced by this nematode are serious and range 20-90% (Bridge et al., 1990).
MEANS OF MOVEMENT AND DISPERSAL: The nematode can be disseminated with infected plant material or transported with irrigation and run off water.
RATING: (L) The damage caused by this nematode is serious. However, its introduction into the U. S. via seeds is unlikely since seeds are not infected. However, it could be introduced in infected plant material such as rice stalks.
REFERENCES:
Bridge, J., M. Luc, and R. A. Plowright. 1990. Nematode
parasites of rice. Pp. 69-108 in M. Luc, R. A. Sikora, and J. Bridge,
eds. Plant parasitic nematodes in subtropical and tropical agriculture.
Wallingford, UK: CAB International.
CAB International 2001. Ditylenchus angustus
in: Crop protection compendium, global module, 3rd edition. Wallingford,
UK: CAB International.
Seshadri, A. R., and D. R. Dasgupta. 1975. Ditylenchus
angustus. CIH descriptions of plant parasitic nematodes, Set 5, No.
64. St. Albans, UK: Commonwealth Institute of Helminthology.