2l8 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 



the Statements as to the relative merits of plants raised from 

 home and foreign-grown seed as disease-resisters, no deduction 

 can be made : and the same may be said of the statements 

 regarding the depth of the soil in which the crops grow. Nothing 

 of a definite nature can be stated, generally speaking, from the 

 information regarding mixtures, but a spruce and larch mixture 

 does not seem to meet with much favour among the observers 

 generally. The majority of the observers are of opinion that 

 there is greater liability to disease in crops which have been 

 planted on land which has been under agricultural crops, 

 especially if it be deep and rich ; but the statements regarding 

 the effect of growing successive crops of larch on the same 

 ground are in direct conflict, as are also those relating to 

 the association of "heart-rot" with the disease. 



One observer states that the disease was first observed about 

 .838. 



Four cases only are instanced of diseased plants having been 

 received from public nurseries. 



Siberian Larch. 



Very little information is given regarding this species. The 

 majority of the observers state that it is less liable to disease, 

 but more liable to injury by frost, than the European species ; 

 and as to its liability to Aphis attack, the very few particulars 

 given are conflicting. 



Japanese Larch. 



Six cases of disease are recorded in the case of this species; 

 but these seem to be, for the most part, isolated cases, and the 

 conclusion, therefore, is that the species is as yet practically 

 free from any serious attack by disease. The majority of the 

 observers state, however, that it is more liable to damage by 

 frosts, especially those of late summer or early autumn, than the 

 European species. Observations on Aphis attack are conflicting, 

 and of attack by other insects, one observer records damage by 

 pine-weevil. 



A. D. Richardson, Convener. 



A. W. Borthwick, D.Sc. 



D. F. Mackenzie, F.S.L 



