602 



V. STEENACKERS 



Table 1. The reaction of clones of four poplar species to 

 various poplar diseases in western Europe 



Clones of poplar species 



Disease 

 organism 



Tccphvina aurea 



P. P. P. P. 



maximowiozii triohocarpa nigra dettoides 



disease score 3 



Marssonina brunnea 



1 1 1 



Marssonina populi 



1? 



Melampsora spp. 



2 2 2 



3 3 3 



4 4 4 



5 5 



Virus 







1? 



Dothiehiza populea 



Aplanob acteri urn 

 populi 







1 1? 



2 2 



3 3 



4 4 



5 5 



Disease scores: = immune, 5 = highly susceptible 



