The dagger nematode is characterized by a 100 μm odontostyle which is used for deep penetration of root tips with its spear-like stylet.
The Xiphinema americanum esophagus is dorylaimoid with an enlarged posterior portion that occupies roughly 1/3 of its total length.
The prerectum of X. americanum measures 120–140 μm long, with a rectum that is roughly the same length as the body diameter at the anus.
Before becoming sexually mature adults, the X. americanum nematodes undergo three to four juvenile stages with a molt occurring between each.
[7] Compounding the issue of determining the life cycle of X. americanum is their difficulty with being grown in culture or greenhouse conditions.
It has been suggested that this is due to X. americanum's sensitivity to moisture tension, temperature fluctuation, physical handling, or oxygen deprivation.
[8][9][10] Field evidence taken over a 2-year observation period indicates that X. americanum are most likely k-selected; they most likely have a long life span and a low reproduction rate.
The states with the highest population of the American Dagger Nematode are Arkansas, California, Pennsylvania, Rhode Island and Virginia.
[14] Other countries where X. americanum is found include Australia, Belize, Brazil, Chile, Guatemala, India, Japan, Korea Democratic People's Republic, Korea Republic, Mexico, New Zealand, Pakistan, Panama, South Africa, Sri Lanka, Uruguay, and areas of the Caribbean as well.
[16] Xiphinema americanum is a plant parasite that lives entirely in the soil and is attracted to young, growing roots due to source–sink dynamics.
Although the nematodes are non-specific in their Host Range, they generally feed on plants that are in poorer condition for a shorter amount of time.
[17] The symptoms that plants exhibit in response to the pathogenicity of Xiphinema americanum are similar to those of other migratory ectoparasitic nematodes of roots.
[17][18] Young, shortleaved yellow pine trees with moderate swelling of roots with clusters of short, stubby branches were the first demonstration of X. americanum pathogenicity in 1955.
[24][25][26][27] TobRSV is a widespread nepovirus in annual crops in North America that infects tobacco, soybean, blueberry, apple, ash, autumn crocus, blackberry, cherry, dogwood, elderberry, grapevine, spearmint, and in Wisconsin has an economically important impact on cucurbits.
[28] TomRSV is another nepovirus transmitted by X. americanum, and is generally a problem with perennial plants including apple, grapevine, raspberry, strawberry, birdsfoot-trefoil, dogwood, elderberry, hydrangeas, orchids, and red currants.
Previous work attempting to identify virus binding sites and release was difficult without the development of immunofluorescent labeling.
[4] Control of the American Dagger Nematode presents problems because X. americanum is hard to completely remove.
Nematicides generally remove up to 95% of the nematodes in soil, however the 5% that remain can reproduce asexually and the viruses that they carry can still infect the roots of young plants.
[30] Additionally, if soil is tilled frequently, X. americanum will likely not be in high enough of a population density to cause any noticeable symptoms in its hosts.