PHYLOGENETIC RELATIONSHIPS OF PLANT PARASITIC NEMATODES:

Looking at a phylogenetic or evolutionary grouping of nematodes can provide useful information to consider when planning a nematode management program.

The scarcity of fossil evidence for plant parasitic nematodes has resulted in the development of a phylogenetic classification system based largely on the morphology of existing species utilizing light and electron microscopes. Now that we have the ability to look at nematodes biochemically and molecularly, it is likely that some changes in the systematics of plant parasitic nematodes will occur.

As long as there are practicing systematists and taxonomists in nematology, revisions to the classification scheme will be ongoing. This table provides a view of a currently accepted phylogenetic classification scheme for commonly encountered plant parasitic nematodes.

Notice that the Phylum Nemata consists of two classes: the Adenophorea (nematodes without phasmids), and the Secernentea (nematodes with phasmids).

Several genera of plant parasitic nematodes are able to transmit viruses to plants. All of these genera are found within the Adenophorea. Therefore, if the results of a soil sample indicate that an Adenophorean nematode is present, one should consider the possibility that the species could transmit plant viruses.

Plant parasitic members of the Adenophorea are migratory ectoparasites, while Secernentea can be either migratory or sedentary, and ecto or endoparasitic.

When developing management options, for example, for a newly found migratory ectoparasite in the family Tylenchulidae one should consider that biologically it is likely to be more similar to the sedentary endoparasite Tylenchulus than to other migratory ectoparasites in the family Dolichodoridae.

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