Mesocriconema xenoplax

Mesocriconema xenoplax is a species of plant parasitic nematodes. Nematodes of this particular species are collectively called ring nematodes. It has a wide host range, infecting many woody plants, and it is known to infect all species of the genus Prunus, which includes peach, almond, apricot, cherry, and plum. It also infects various other fruit trees, and grapes, in particular. There have been studies that have shown large concentrations of ring nematodes in peppermint, as well.Symptoms can include, but are not limited to: root-pruning, decreased nutrient uptake, vascular damage, possible death of shoots and limbs, and stunted plant growth. With the reduced nutrient uptake, some cases have shown that the change in ratio if carbon:nitrogen can make plants infected by ring nematodes more susceptible to bacterial canker cause by Pseudomonas syringae, (Lownsberry, et al. 1977). Ring nematodes are easily distinguished by distinctive coarse ridges, known as annulations, around the body. Females have a long, wide stylet, and have 'knobs' that allow for the attachment of the stylet muscles. Head is broad, and the lip region shape is variable and sometimes there are four extra submedial lobes. The tail is broadly round, and the terminus is most often a small, simple, rounded button. The vulva is very distinctly open, and appears more posterior than usual. Male ring nematodes tend to be much thinner than females, and they lack a stylet. They also lack a distinct esophagus, which renders them incapable of feeding. Their spicules are simple and slender, and can be straight or slightly curved.