VI CONTENTS 



Page 

 Dangerous forest diseases in western Europe 73 



Scots pine blister rust F. Roll-Hansen 



Larch canker and dieback H. Robak 



Hypodermella needle cast of pine H. Robak 



Pine twist rust J. Gremmen 



Top canker of spruce and pine E. Bjorkman 



Dangerous forest diseases in North America 82 



Introduction 82 



Brooming disease of black locust T. J. Grant 



Phloem necrosis of elm R. U. Swingle 



Atropellis canker of pine J. C. Hopkins 



Persimmon wilt G. H. Hepting 



Oak wilt C. E. Seliskar 



Canker stain of plane trees Curtis May 



Clitocybe root rot W. A. Campbell 



Spruce broom rust R. S. Peterson 



Comandra blister rust J. L. Mielke 



Southern fusiform rust A. F. Verrall 



Eastern gall rust J. E. Nighswander 



Ponderosa pine needle cast T. W. Childs 



Gray blight of hard pines G. D. Darker 



Hypoxylon canker of aspen J. R. Hansbrough 



Cedar leaf blight J. S. Boyce 



Western gall rust (woodgate rust) W. G. Ziller 



Stalactiform rust W. G. Ziller 



Cedar blight G. W. Peterson 



Phymatotrichum root rot Ernest Wright 



Poria root rot of Douglas-fir G. W. Wallis 



Fir tip blight M. E. Fowler 



Brown-spot needle blight A. F. Verrall 



Septoria canker of poplars J. E. Bier 



Strumella canker of oaks J. R. Hansborough 



Dwarf mistletoes of conifers Job Kuijt 



Principles of forest disease control J. S. Boyce 



Lessening the threat of internationally danger- 

 ous tree diseases A. J. Riker 



Discussion and recommendations 122 



