Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/3/2001
Publication Date: 10/1/2001
Citation: Interpretive Summary: The distribution of longidorids (i.e., dagger and needle nematodes) on Prunus in the southeastern United States is largely unknown. Dagger nematodes in particular are known economic pests on peach in the Northeast and California. Determining the incidence of these nematodes on peach in the Southeast needs to be investigated. In April 2000, Dr. Franco Lamberti, Nematologist from the Instituto di Nematologia Agraria, Bari, Italy, visited the SE Fruit and Tree Nut Research laboratory in Byron, Georgia. The purpose of this visit was to obtain as many longidorid species from fruit and native tree species in Georgia. Preserved specimens were taken back to Italy for classical taxonomical examination. Results of the survey indicated that a Xiphinema sp was recovered from soil around both healthy and dying peach trees in a particular orchard. Following a comparative microscope study, the species was identified as Xiphinema pacificum. These data provide useful insights into the distribution of Xiphinema pacificum on peach, since this is the first report of this nematode species within the United States.
Technical Abstract: In April 2000, a Xiphinema sp was found in a peach (Prunus persica L. Batsch) orchard during a longidorid nematode survey, in Concord, Georgia. This site was of particular interest in our survey, because the nematode was recovered from the rhizosphere of healthy and dying peach trees established on Lovell rootstock. In spring 1999, tree death from bacterial canker (Pseudomonas syringae pv. syringae) occurred within this then 2-year-old orchard. Soil samples indicated that the population density of this Xiphinema sp and a Pratylenchus sp were greater under dying trees than under healthy trees. Roots of declining trees did not exhibit characteristic root tip gall symptoms of longidorid feeding activity. Following classical nematode taxonomic analysis, the nematode was identified as Xiphinema pacificum. All morphometric measurements coincided well with the original description. This nematode was originally described from British Columbia, Canada, where it seemed to be restricted in its distribution to vineyards of the south Okanagan valley. This is the first report of X. pacificum in the United States.