F. T. Brooks and M. A. Bailey 205 



(6) Experimenls tvilh apple trees. 



As recorded in 1913(2) few inoculations of apple trees with Sferetwi 

 purpurenm have resulted in silver-leaf. Three other trees of the Lord 

 Suffield variety became silvered after inoculation with sporophores of 

 Stereiiin pvrpiirei(m, but other varieties (Lane's Prince Albert, Stirling 

 Castle, Bramley's Seedling) inoculated either with sporophore or pure 

 culture material of this fungus or with sporophores of Stereum, hirsutum 

 have remained unsilvered. 



Reference has already been made (2) to the frequency of silvering 

 in scions of regrafted apple trees in fruit plantations. We have had 

 apple trees regrafted in order to keep them under observation in this 

 connection : seven Bramley Seedling trees, and five Stirling Castle trees 

 about five years old were cut back and regrafted in different ways with 

 scions of Bramley Seedling either at the end of the main stem or in 

 lateral branches. 



An interval of a month, elapsed between the cutting back of the 

 stocks and the insertion of the scions which had been heeled into the 

 ground for some time before use. After insertion of the scions, all 

 exposed surfaces were covered with grafting wax. Most of the scions 

 developed and formed healthy shoots during 1913 and 1914 but one of 

 them became silvered during the summer of 1915. At the same time 

 four old apple trees (two Codlin, one Warner's King, one French Crab) 

 were regrafted with scions of Bramley Seedling. It is worth while to 

 consider these trees in detail. 



(1) Codlin. Seven scions of the twelve inserted grew well during 

 1913 the foliage being normal. By June, 1914, however, some leaves 

 of each scion were silvered and the affection became more clearly 

 marked as the summer advanced. During March, 1915, the upper parts 

 of this tree bearing the scions were cut off in order to see if there was 

 any considerable discolouration of the wood. This was present in 

 quantity and up to distances of nearly a foot from the point of insertion 

 of the scions. 



There were several places from which the disease may have spread 

 in the tissues. The exposed ends of the stock after the grafting wax had 

 fallen ofi, dead scions, and the scars made by cutting away lateral 

 branches below the scions, were all centres from which a fungus may 

 have spread into the neighbouring tissues. The zones of discolouration 

 relating to these areas often ran into one another and it was impossible 



Joum. of Agrio. Sci. is. 14 



