120 



EXPERIMENTAL FARMS 



5-6 EDWARD VII., A. 1906 



whicli has been grown at the Central Experimental Farm for the past seventeen years, 

 proved to be the most blight resistant as well as one of the most productive. It yielded 

 at the rate of S16 bushels 48 lbs. per acre. About equally as resistant to blight but 

 much lower in yield were : June, 189 bushels 12 lbs. per acre ; Eust Proof, 118 bushels 

 48 lbs. per acre; Sutton's Discovery, 66 bushels per acre. Almost equally resistant 

 were Clay Rose, 215 bushels 36 lbs. per acre; Rural Blush, 206 bushels 48 lbs. per acre, 

 and Dr. Maerker, 158 bushels 24 lbs. per acre, and State of Maine, 149 bushels 36 lbs. 

 per acre. The dates when the tops showed the first signs of disease; when the leaves 

 were dead; and when the stems were dead, were all noted and the yield per acre rc- 

 dorded of all the varieties tested. 



The disease did eventually attack the foliage of those most resistant and as these 

 are all late varieties some of them did not yield as much as other earlier kinds a little 

 less resistant. The disease developed early this year, which accounts, no doubt, for the 

 fact that the yields from some of the most blight resistant but latest varieties were 

 comparatively small. It is evident that a variety can be so late in season that it will 

 not resist blight long enough for a crop to be developed which will equal a variety a 

 little earlier in season though apparently not so resistant. The potatoes from the best 

 hills of the most blight resistant varieties were saved for the purpose of continuing this 

 test in the hope that by careful selection more productive and more blight resistant 

 strains will be developed. 



Spraying Potatoes to Prevent Blight and Rot. — The prevalence of blight and rot 

 in the provinces of Ontario and Quebec this year will, it is hoped, draw the attention 

 of farmers more than it has done in the past to the value of Bordeaux mixture in pre- 

 venting this disease. During the past fourteen years experiments have been conducted 

 at the Central Experimental Farm with the object of testing different remedies, but up 

 to the present time nothing has proven as satisfactory as Bordeaux mixture. An esti- 

 mate of the cost of applying Bordeaux mixture has been given in previous reports and 

 ♦inv-^a bulletin on potato culture published this year. Briefly stated, it may be said that 

 the cost of four applications per acre was estimated at $5.52. As this estimate was 

 based on comparatively small plots it would be somewhat reduced on large areas. As 

 the disease may make its appearance any time during the latter part of July, it has 

 been found to be the best practice to spray about the middle of July, or even before, if 

 one has to spray for the potato beetle about that time. The formula recommended is : 

 6 lbs. bluestone, 4 lbs. lime, 40 gallons water. 



Following are the results obtained from the use of Bordeaux mixture, including 

 this year. It will be seen that the average increase from spraying for four years is at 

 the rate of 92 bushels 31 lbs. per acre. At 40c. a bushel this would mean an average 

 net profit per acre from the use of Bordeaux mixture of about $30, deducting the cost 

 of application. 



