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. They are of agricultural concern because they are vectors of nepoviruses, transferring them during feeding. Efforts to study these nematodes in more detail have proved problematic in some species due to difficulties in maintaining populations in a greenhouse environment.