Xiphinema

Genus of roundworms

Xiphinema is a genus of ectoparasitic root nematodes commonly known as dagger nematodes. The genus is of economic importance on grape, strawberry, hops and a few other crops. Major species include X. americanum, X. diversicaudatum, X. index, X. italiae and X. pachtaicum. They can be easily recognized by their long bodies and stylets which are long enough to reach the vascular tissue of plants. Different members of the genus have been shown to induce moderate to large amounts of root damage through root penetration, which in some species results in the formation of galls. Efforts to study these nematodes in more detail have proved problematic in some species due to difficulties in maintaining populations in a greenhouse environment.

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.

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. Males can be abundant or sparse depending on the species, which may suggest the presence of both parthenogenic and amphimictic species.

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.