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narily potatoes should not be grown oftener on the same land than every 

 fourth year. Where Powdery Scab has existed, it is advisable to change 

 to land that has not previously produced a diseased crop of potatoes. The 

 infected land may be used for any other crop with the exception of potatoes. 



Stable Manure and Artificial Fertilizers in Relation to Common 



Scab. 



From the disease point of view, stable manure should not be used for 

 potatoes. This is likely to result in a scabby crop, which is largely averted 

 by the use of fertilizers. When there is a lack of humus in the soil, an 

 application of crumbled peat will be found useful. This will also retain 

 the moisture in light soils. 



C. The Diseases of the Growing Plant. 



The recognition of diseases noticeable only in the growing plant will 

 invariably be most difificult. Where doubt exists, a specimen showing 

 the suspected trouble should be mailed to the Dominion Botanist for his 

 advice, but, generally speaking, careful attention to the eliminatiiOn of 

 disease in the seed tubers will have largely reduced the disease aiTecting 

 the growing plant. Farmers should make it a rule to immediately remove 

 any individual hill that may show signs of yellowing, curling-up of leaves 

 or otherwise feeble growth, as well as any individual plant with flowers 

 of a different colour from the rest, in order to keep varieties pure. 



D. Spraying. 



1. Spraying is practised for two main reasons: First, to control the 

 Colorado Beetle; and second, to control Late Blight. There are other 

 minor reasons. 



2. Experiments have shown that several solutions will destroy the 

 Colorado Beetle, but the solution acting most rapidly is the one to use. 



3. Spraying must be done thoroughly. All plants, and all parts thereof, 

 must be well covered. A plant with one half sprayed and the other half 

 missed will have the unsprayed part eaten off by the beetles very quickly. 

 This will leave enough beetles to continue the pest. One spray thoroughly 

 applied is better than several carelessly applied. 



4. We recommend two special applications for beetles; one when the 

 plants are from four to six inches high, to be followed by another from one 



