PREFACE 
Tus book arose from an investigation which Sir William 
Schlich. asked me to make into the larch canker, a disease 
on which many articles and papers have been published, 
though no full and connected account of it has ever been 
written in English. While studying the canker in the field, 
I very frequently encountered certain other diseases on the 
larch, especially the heart-rot and the honey fungus, and it 
seemed better to include these in the scope of the investi- 
gation. For the sake of completeness, all the known diseases 
on the common larch have also been described, and it is 
hoped that a book of more general usefulness has been 
thereby produced. Certain fungi, such as Lophodermium 
laricis and Botrytis cinerea, which have occasionally been 
reported as parasitic on the larch, have been omitted, as no 
reliable evidence of their causing disease has been forth- 
coming. 
The arrangement of the diseases bears no relation to the 
systematic position of the fungi. They are mostly given in 
the order in which they were studied, which approximates 
closely to the order of their importance. 
The work was made possible by a grant from the De- 
velopment Commissioners, received through the Board of 
Agriculture and Fisheries, and latterly through the Interim 
Forest Authority. Especial acknowledgement is due to 
these departments, particularly to the last named, which 
has assisted me in a variety of ways. I also desire to thank 
Sir William Schlich for constant help and encouragement, 
and Messrs. A. W. Borthwick and Malcolm Wilson for 
permission to reproduce Fig. 72 irom the T'ransactions of 
the Royal Scottish Arboricultural Society. 
OxFoRD, August 1919. 
