Aphelenchus avenae is a common soil inhabiting nematode which feeds on fungi but also cases of Aphelenchus in healthy plant tissue have been recorded; as far as known they don’t damage higher plants. Aphelenchus can easily be cultivated on fungi and therefore, it is a suitable organism in experiments. A number of species have been described in the genus Aphelenchus but specialists doubt if it are good species or that A. avenae is a morphological variable species. In the Netherlands, the only specimens found are females; in southern Europe males are quite common. If we cultivate dutch material at higher temperature, also males are formed.