PLANT DISEASES DUE TO FUNGI. 47 



like patches on the surface, not unfrequently covering the whole of 

 the tuber, and thereby considerably depreciating their market value. 



Thaxter has shown, that as the result of extensive experiments 

 made by him, that a complete specific is afforded by soaking the seed 

 potatoes in a solution of one pint of formaldehyde in fifteen gallons 

 of water, for a couple of hours. The Board of Agriculture recommend 

 one pint of formaldehyde in thirty-six gallons of water. 1 



In addition to the potato, swedes, beet, carrots and cabbages are 

 attacked by this fungus, so that cereals should be sown on land where 

 the potato crop in the previous year has shown the disease. 



Although growers are generally agreed that this disease 

 is favoured by the presence of lime in the soil, more carefully planned 

 experiments and further evidence on this point are very desirable. 



Stable manure and night-soil should be avoided, and acid manures 

 only put on to infected land. 



YELLOW WART DISEASE. 



Synchytrium solani (Massee). 



From various localities diseased tubers have been received. 

 Some futher experiments have been made on treating the soil with 

 lime and sulphur, and others are in progress. 



As Mr. George Massee 2 remarks in his recent and excellent hand- 

 book, " The only methods that can be suggested for checking the 

 spread of the disease are of a preventive nature, and as these are 

 unfortunately mostly outside the range of what may be expected of 

 the potato-grower, or, for the matter of that, any one else, the field 

 is open for the stump-orator, whose energies are expended in 

 denouncing the powers that be for not promptlv suppressing all traces 

 of the disease from the British Empire. Difficulty No. i consists in 

 the fact that a potato used for ' seed ' may be so slightly infected 

 that the disease would not attract the attention even of an expert. If 

 such a potato is used for ' seed ' a diseased crop will probably result, 

 at all events the land in which the crop grew will be infected. Diffi- 

 culty Xo. 2 turns on the fact that when land is once infected it remains 

 in a condition capable of imparting the disease to potatoes after 



1 Leaflet N'o. 137, March, 1905. Revised, March, 1906. 



2 Diseases of Cultivated Plants, 1910, p. 102. 



