116 



EXPERIMENTAL FARMS. 



POTATO SCAB. 



A large amount of experimental work has been devoted by station workers to the 

 potato disease known as " scab." To Prof. Bolley, of North Dakota Experimental 

 Station, is due the credit of discovering the nature of the malady, and a remedy — 

 corrosive sublimate — which has proved eminently successful in fighting the disease. The 

 dangerously poisonous character of the remedial agent gives it a decidedly undesirable 

 feature. In searching for a germicide less harmful to the person handling it. Prof. 

 Arthur, of the Indiana Experiment Station, reported last winter, through the columns 

 of the agricultural press, and later by special bulletin, that formalin (formic aldehyde), a 

 lately introduced and harmless antiseptic substance, had given him better results in 

 combating potato scab than had corrosive sublimate. 



While potato scab is not in potato culture in Eastern Canada a disease of the first 

 importance, yet a considerable percentage of the potato crop is rendered unsaleable by 

 this disease each year. Some experiments were therefore planned and carried out, having 

 for their object the determination of the comparative value of various substances in 

 preventing this disease. Two varieties of potatoes — Clark's No. 1 and Northern Spy — 

 were selected for the trial. The potatoes were washed and found to be an average 

 sample, with a fair proportion of scabby specimens. Each variety was divided into 18 

 lots of 5 pounds each, care being taken to make the samples as even as possible as to 

 quality. Each sample was soaked for two hours in one of the germicidal solutions. In 

 the case of sample H the potatoes, when cut, were rolled in the flowers of sulphur. 

 They were all planted. May 21, on a clean piece of unmanured, sandy loam. They were 

 given good cultivation and sprayed to prevent injury from potato bugs. Each lot 

 occupied 50 feet in the row. The crop was harvested on September 29, the rotten 

 potatoes being separated from the sound and weighed. In order to get an estimate of 

 the percentage of scabby potatoes, an average peck of the produce of each sample planted 

 was selected and the number of diseased specimens counted out. Full particulars are 

 given in the subjoined tabular statement. 



EXPERIMENTS TO PREVENT POTATO SCAB. 



Potatoes planted 21st May ; Harvested 29th September ; 5 pounds of seed used in 

 each case. Each row 50 feet long. 



.f Clark's No. 1. 

 t Northern Spy. 



g /Clark's No. 1. 

 \ Northern Spy, 



Check- 

 Clark's No. 1. 

 Northern Spy 



qT Clark's No. 1. 

 \ Northern Spy 



jjf Clark's No. 1. 

 \ Northern Spy 



Check— 



Clark's No. 1 

 Northern Spy 



Weight 

 of Sound 

 Potatoes. 



Lbs. Oz. 



69 .. 



51 .. 



60 . 

 59 8 



62 

 66 



70 

 71 



45 

 66 



50 

 69 



Weight 

 of Rotten 

 Potatoes. 



Number 



of Scabby 



Potatoes 



in a Peck . 



Lbs. Oz. 



3 8 



3 8 



4 .. 

 3 8 

 3 .. 



3 



2 



17 

 4 



20 



7 

 3 



12 

 1 



43 



Number 



of Clean 



Potatoes 



in a Peck . 



85 

 42 



75 

 33 



70 



48 



72 

 49 



94 



42 



33 

 35 



