Xiphinema

Mouth section of a Xiphinema sp. juvenile

Xiphinema are large nematodes, with an adult length between 1.5mm – 5.0mm.[1] They have a long protrusible odontostyle, with 3 basal flanges at the posterior end of the stylet and a relatively posterior guiding ring when compared to the genus Longidorus.[3] The odontostyle is lined with cuticle and alongside the esophagus serves as a good surface for viruses such as arabis mosaic virus to form a monolayer, which can be vectored to healthy plants.[4] Xiphinema have a two-part esophagus, which does not contain a metacorpus. A modification in the posterior end of the esophagus forms a muscular posterior bulb, which can generate a pumping action similar to that of a metacorpus in other plant parasitic nematodes.[4] The number of males varies from abundant to sparse depending on the species.[1] Males have paired spicules but the gubernaculum and bursa are absent. Males of different species can be characterized using the varying number and arrangement of papillae.[3] Females have 1 or 2 ovaries.[3]

There are 296 nominal taxa, including 234 accepted species, 49 synonyms and 13 species inquirendae.(He 2003)

The genus Xiphinema is distributed worldwide. Two economically important Xiphinema species, X.index and X.americanum, are both commonly found in California and tend to be problematic in vineyards. X. diversicaudatum is also found in parts of the U.S, as well as Europe and Australia.[3]

Eggs are laid singly in thin water layers in the soil and are not part of an egg mass. After the first-stage juvenile emerges from the egg there are 3 or 4 molts, all of which occur in the soil.[3] Males can be abundant or sparse depending on the species, which may suggest the presence of both parthenogenic and amphimictic species.[3]

Xiphinema has a very wide host range including crops of high economic importance such as grape, hops and strawberry. Other documented hosts include: Nectarine, oak, rose, grapevine, raspberry, carrot, cherry, peach, and soybean.[3]