1128 



Potato Pink PvOt. 



[Mar., 



that county. The fungus when isolated and cultivated 

 developed resting spores of P. erythroseptica in the typical 

 manner, thus confirming the Inspector's diagnosis in the 

 field. The variety in this case was Great Scot grown from 

 Scotch seed. The disease was first detected on 22nd August, about 

 five per cent, of the plants in a five-acre field being affected. 

 It was observed to be worse in some parts of the field, especially 

 the low-lying portions. A careful survey of the neighbouring 

 district was made by Mr. Jarrett and the disease was found to 

 be present to a small extent in a number of fields in several of 

 the adjoining towns and villages. In all, six localities were dis- 

 covered, the variety in each case being Great Scot, the 

 seed being obtained from Scotland. Local opinion indicates 

 that there is some ground for believing the disease to have 

 been present in previous seasons in these .districts and that 

 it was not introduced in. 1921 with Scotch seed. On the other 

 hand the fact that Great Scot only was affected is rather against 

 this view. 



The other case occurred near Stevenage, in Hertfordshire, 

 specimens being submitted by a farmer. The variety was King 

 Edward and was grown on land which had not been under 

 potatoes for five years. The seed was home-saved and the crop 

 during 1920 showed no signs whatever of Pink Eot. The seed 

 therefore was almost certainly not the means by which the 

 disease was introduced. Its origin, however, is probably easy 

 to account for. The field in question had been heavily dressed 

 with " London manure." This contained a large amount of 

 vegetable debris such as cabbage stalks, banana stalks, onion, 

 orange and potato refuse, indicating that the manure was con- 

 taminated with street sweepings or even market refuse. There 

 can be little doubt thai in this case the disease was 

 introduced with the manure, which contained resting spores 

 of Pink Rot in potnto peelings and possibly even diseased potatoes 

 which had been thrown out on account of being rotten. The 

 Stevenage case appeared to be an isolated one, no other affected 

 fields being observed in the neighbourhood. The field in ques- 

 tion was three acres in extent, the disease occurring in patches; 

 in the worst parts thirty-five per cent, of the plants were affected. 

 The tops of the diseased plants died dowu early and every tuber 

 on the roots was completely rotted with a moist rot. 



Description of the Disease.— The fungus causes a wilting of 

 the haulm and a moist rot of the tubers, the disease deriving its 



