NOTE ON TAXONOMY AND BIOLOGY: Females of this needle nematode are 3.3-4 mm long. They have the guide ring located 50-64 µm from the anterior end. The odontostylet and odontophore are 109-121 and 55-66 µm long, respectively. Their tail is rounded. This needle nematode has ectoparasitic habits and feeds on root tips causing small apical galls. It requires one or more years to complete its life cycle. Males are not known. This nematode vectors the peach rosette mosaic virus (PRMV).

GEOGRAPHICAL DISTRIBUTION: Longidorus diadecturus has been reported only in Canada.

HOSTS: The nematode parasitizes peach trees (Prunus persica) under field conditions. Under greenhouse conditions the nematode has been able to transmit the PRMV to cucumber (Cucumber sativus) and grape (Vitis vinifera.) (Allen et al., 1982).

CROP LOSSES: There is no information on the direct damage induced by this nematode, however, PRMV, which is vectored by the nematode, is the agent of a serious disease in peach trees, grape and blueberry (Vaccinium sp.) (Brown, et al., 1993; Nyczepir and Halbrendt; 1993; Stace- Smith and Ramsdell, 1987).

MEANS OF MOVEMENT AND DISPERSAL: Longidorus attenuatus is dispersed with infested soil, poorly sanitized bare rooted plants or contaminated machinery.

RATING: (L) Although this nematode should be excluded if detected, it was given a low priority rating for a complete risk assessment, because it is an ectoparasite and the primary entry pathway would be mineral soil which currently cannot be imported with plants.

REFERENCES:
    Allen, W. R., J. G. Van Schangen, E. S. Eveleigh. 1982. Transmission of peach rosette mosaic to peach, grape and cucumber by Longidorus diadecturus obtained from diseased orchard in Ontario. Canadian Journal of Plant Pathology 4:16-18.
    Brown, D. J. F., A. Dalmasso and D. L. Trudgill. 1993. Nematodes pests of soft fruits and vines. Pp.427-462 in K. Evans, D. L. Trudgill, and J. M. Webster eds. Plant Parasitic Nematodes in temperate Agriculture. Wallingford, UK: CAB International.
    Nyczepir, A. P., and J. M. Halbrendt 1993. Nematode pests of deciduous fruit and nut trees. Pp. 381-425 in K. Evans, D. L. Trudgill, and J. M. Webster eds. Plant Parasitic Nematodes in temperate Agriculture. Wallingford, UK: CAB International.
    Stace-Smith, R., and D. C. Ramsdell. 1987. Nepoviruses of the Americas. Pp. 131-166 in K. F. Harris ed. Current topics in vector research. New York: Springer-Verlag.