190 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 



The effect of the disease on the rhododendron is not serious ; 

 on the spruce the diseased needles fall in the summer of infection, 

 and in severe cases the trees may be almost stripped of foliage. 



Chrysomyxa abietis, Wallr. The Needle Rust of the Spruce. 



Chrysomyxa abietis was first recorded in Scotland by Somer- 

 ville/ from Durris near Aberdeen, and, writing in January 1915,^ 

 the same investigator stated that up to that time he had received 

 no further reports of its occurrence. A quantity of the fungus 

 vwas recently obtained from Aberdeenshire, and in view of the 

 omission of this species from recent works on British Uredineae, 

 .as well as of its importance as a disease of the spruce, further 

 inquiries as to its distribution in Scotland have been made. 



Professor Trail has kindly forwarded the following 

 information : — 



"It is not more than six or seven years ago that I first 

 observed Chrysomyxa abietis in Aberdeenshire, and it is probable 

 that the fungus has only recently made its appearance in the 

 north of Scotland. I have seen trees attacked by the disease 

 in the Monymusk and Farland districts. The disease is now 

 also very common in the spruce woods on the banks of the 

 Findhorn, where it was first noted some three or four years ago 

 by Mr William Watt, Assistant Forester on the Moray estates. 

 When the infected trees in this locality are standing singly and 

 foliaged to the ground, only the leaves on the lower branches 

 are as yet attacked." 



Mr P. Leslie, Lecturer in Forestry at the North of Scotland 

 College of Agriculture, informs us that Chrysomyxa abietis is 

 stated to be quite common on the Novar estate, Ross-shire.^ It 

 is evident, therefore, that the disease is spreading to a consider- 

 able extent. 



Chrysomyxa abietis, which is widely spread in Switzerland 

 and Germany, is an autoecious species completing its life-history 

 on the spruce. It differs from C Rhododendri in producing 

 only one kind of spore, the teleutospore. The hibernating 

 teleutospores germinate about May and produce sporidia which 



1 Quart. Journ. Forestry, vol. v., p. 277, 1911. 



' Quart. Journ. Forestry, vol. ix., p. 68, 1915. 



' In material from Novar the Chrysomyxa abietis is itself attacked by the 

 parasitic fungus Darluca Filum, Cost. Further investigations will be carried 

 out to determine how far it is possible to check the ravages of the disease by 

 inoculation with this parasite. 



