114 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 
POTATOS : EXPERIMENTS IN CULTIVATION, ETC. 
Note. — The experiments, the results of which are given below, were 
planned by the Wisley Staff in consultation with the Wisley Develop- 
ment Committee and were carried out by Messrs. Chittenden, 
Wright, and Wilson, with the assistance of Mr. W. Rogers in weigh- 
ing the crops. -The labour involved in conducting and recording such 
experiments is great, and the Council feels that the special thanks of 
the Society are due to these members of the Wisley Staff for under- 
taking and carrying them to a successful conclusion, in spite of depleted 
staff and much additional heavy work. 
Those conversant with the way in which wart disease is spreading 
will recognize the importance of tests in respect to the relative cropping 
and cooking qualities of wart-resisting varieties (see below). 
Next in general interest to the trial of wart-resisting varieties is 
the spacing experiment (see p. 127). Needless to say, such experi- 
ments must be repeated in different soils and with different varieties 
before the results can be expected to influence general practice ; the 
results obtained this year at W isley point so uniformly to the conclusion 
that the closer planting gives the larger yield, that it may fairly be 
concluded that on such good potato soils as that at Wisley the closer 
planting may with advantage be practised, with the proviso that the 
closer the planting the greater the need for early and thorough spraying. 
Frederick Keeble, 
Director. 
WART-RESISTANT POTATOS AT WISLEY, 1917. 
The tumour, black scab, or wart disease of potatos, caused by the 
attack of the fungus Synchytrium endobioticum (or Chrysophlyctis 
endobiotica) , fully described in the Journal R.H.S. xxxvii., p. 362, has 
spread so far and so steadily that there seems grave danger that, in 
spite of all efforts to prevent it, the whole of the country will before 
long be infected. No soil or tuber treatment has yet been discovered, 
although much investigation has been carried out, which will control 
or even lessen the virulence of the disease, and the only means at 
present known of procuring a healthy crop of potatos when this fungus 
is present in the soil is to grow one or other of the varieties which the 
trials carried out by the Board of Agriculture have shown to be immune 
from attack. 
The varieties which the Board has ascertained to be immune 
were (with two or three exceptions) collected from various sources 
and grown side by side at Wisley in 1917, in order to compare their 
