10. 



Tylenchorhyncnus species 



Tne most abiindant genus both in species and numbers is Tylen- 

 chorhynchus . In most soils in Europe several hundred to several 

 thousand specimens of one or more species are generally found. 



After VOGEL (1958) Tylenchornynchus claytoni is the cause of 

 root rot and poor growth of azalea in Switzerland. The writer found 

 tnis species in the Netherlands in soil around roots of Kalrria , a 

 shrub imported from North America, and azalea. Probably T, claytoni 

 was brought in on these shrubs. 



No damage by other Tylenchorhynchus species has been reported. 



Dorylaimoid species 



Of the dorylaimoid plant parasitic genera Trichodorus is found 

 in almost any field in the Netherlands. T. pachydermus occurs most 

 generally, but also T, primitivus is wideTy spread. So far, no 

 damage by these nematodes wliich seldom occur in large numbers has 

 been reported. 



On the contrary, Xiphinema species are rare. 



