I02 NOTES ON APPLE AND POTATO DISEASES 



ments are here reported. In these experiments the potatoes 

 were planted on ground which had probably not been used for 

 this crop for many years at least. The seed potatoes selected 

 were badly scabbed. Part of the seed was planted untreated ; 

 the other part was treated with corrosive sublimate in the man- 

 ner to be described later. Treated and untreated seed was 

 planted in plots side by side, under similar conditions of soil 

 and fertilzation. When the potatoes were harvested the un- 

 treated plots in field A, gave 48 per cent, scabb}', and 53 per 

 cent, free from scab ; the treated plots gave 17 per cent, 

 scabby, and S3 per cent, free from scab ; a gain of 31 per cent, 

 in favor of the treatment. 



A similar experiment in another field (field B) gave from 

 untreated seed 35 per cent, scabby and 6^ per cent, free ; from 

 treated seed, 13 per cent, scabby and 87 per cent, free, or a 

 gain of 23 per cent, in favor of the treatment. 



Method of Using Corrosive Sublimate. — Dissolve corro- 

 sive sublimate in water at the rate of one ounce to eight gallons 

 of water. Keep this solution in a wooden vessel ; a barrel, half 

 barrel, or w'ashtub will answer the purpose. Put the potatoes 

 to be treated in a coarse sacking bag, and plunge in the solu- 

 tion ; let them remain for an hour and a half, moving them 

 about occasionally to insure thorough wetting ; then drj- the 

 potatoes, and they are ready for planting. Care should be 

 taken that they do not become contaminated again by dirt from 

 untreated potatoes. It should be remembered that corrosive 

 sublimate is a violent poison if taken internally, therefore care 

 should be taken in using it. 



For7naline. — This is a liquid which has recently come into 

 prominence as a valuable disinfectant. It is sold under various 

 names, '' Formalin," " Formine," " Formalose," "Formalde- 

 hyde," and is usually a 40 per cent, solution of formaldeh3'de 

 ofas in water. 



In our experiments with this substance as a remedy for potato 

 scab two strengths were used, viz. : One pint to 33 gallons of 

 water, and one pint to 3i gallons of water. The potatoes were 

 soaked in these solutions for two hours. They were planted 

 alongside the corrosive sublimate plots in field A, and under 

 the same conditions, the same untreated plots serving as checks 



