114 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 



In conclusion there can be little doubt that the attacks of 

 H. aspersa on the recently transplanted young sycamores at 

 the Marine Laboratory throughout these years (though over- 

 looked till now) have aided in their destruction. The soil, no 

 doubt, was indifferent since it was largely mixed with the under- 

 lying sand, and the exposure of the leaves to winds often briny, 

 together with the effect of the sun, rendered the injuries by the 

 snails to the bark the last straw in the struggle. 



10. A New Disease of the Silver Firs in Scotland. 



( With Plates.) 



By Malcolm Wilson, D.Sc, F.R.S.E., F.L.S., Reader in Mycology, 

 University of Edinburgh, and James Macdonald, B.Sc. 



Comparatively little attention has been paid to the diseases 

 of the silver fir in this country, although during recent years it 

 has suffered so severely, that in some localities its cultivation 

 has been discontinued. 



One of the most serious diseases at the present time is that 

 caused by the fungus Rehmiellopsis bohemica. Although this 

 species was first described in Bohemia in 1910 by Bubak,i it 

 had been collected in 1905 by Dr. A. W. Borthwick in 

 Midlothian, and again in 1909 in East Lothian. In all these 

 cases it was found attacking the common silver fir, Abies 

 pectinata. In recent years, the disease appears to have been 

 spreading rapidly, and is no longer confined only to A. pectinata. 

 It has now been found on A. nobilis, A. Finsapo, A. Pindrow, 

 and A. cephalonica. At present the disease appears to be 

 spreading, especially over the southern and western parts of 

 Scotland. It has been found in southern Inverness, northern 

 Perthshire, Argyll, Wigtonshire, Peebles, and Mid and East 

 Lothian. The disease attacks young trees with great severity, 

 and on older trees is generally found on the lower branches. 

 So far as is known, large trees of A. pectinata^ probably from 

 fifty to eighty years old, are not attacked, even although they 

 may be in close proximity to heavily infected young plantations. 



The fungus almost always attacks the leaves of the current year, 

 usually very soon after they expand (PI. IV., Fig. 3). The leaves 

 rapidly shrivel, at first becoming slightly reddened (especially in 

 ^ Bubak, Natur. Zeitsch.f. Forst-tt. Landw., 8, 1910, p, 313. 



