170 PRODUCTIVE FARMING 



fight the beetles. Plan to fight them both at each spraying, 

 by combining the poison with the Bordeaux. See preceding 

 paragraphs. 



Two kinds of potato blight affect the crop, namely 

 early blight and late blight. They both turn the vines brown 

 and gradually kill them. They are both effectually prevented 

 by using Bordeaux in advance of the disease, say every 

 time that poison is needed to kill potato beetles or flea beetles. 



The early blight is much less destructive in most States 

 than the late blight. Growers do not always find it practical 

 to spray to prevent early blight. But as Bordeaux mixture 

 is not expensive and if the work of spraying for beetles 

 is done earty, it is advisable to use both the poison and the 

 Bordeaux together. 



Late blight is usually very common. Most unsprayed 

 crops are affected by it. The vines die too soon; the yield is 

 much reduced; the tubers ripen prematurely; and the pota- 

 toes will not keep in storage so well. The so-called " centre 

 rot" and "end rot" of the tubers at harvest time and later, 

 are results of the attacks of late blight. It was this potato 

 blight which caused the terrible famine in Ireland hi 1846. 



There is no excuse for not preventing this disease by 

 spraying with Bordeaux mixture while spraying with poison 

 to fight the beetles. (See Appendix, Table III, for making 

 Bordeaux mixture.) 



Potato Scab Disease. This is a serious trouble in nearly 

 all potato-growing districts. If all seed potatoes are given 

 a preventive treatment before planting, the soil will be kept 

 free from the disease and the crop will not be affected. 



Before cutting the tubers, soak them for two hours in a 

 solution of one pint full strength formalin in thirty-two 

 gallons of water. Applications of fresh lime or fresh manure 

 both tend to increase the scab disease in the soil. These 

 should both be avoided when potatoes are planted. 



Harvesting. Large potato fields are usually dug by use 



