76 DISEASE AND ITS PREVENTION 



seed piece or soil, it will make its appearance sooner or later, 

 and, if the disease is to be prevented, it should be taken in 

 time. 



Some growers advise first spraying the plants when a 

 certain age. Would it be wise if smallpox, or any dreaded 

 disease, prevailed in a family, and some had been exposed 

 to it, to wait until the child was a certain age to vaccinate ? 

 No, this should be done early, in order to prevent it. This 

 same precaution should be considered in the growing of a 

 crop of potatoes. 



After the first spraying, the plants should be sprayed 

 about every two weeks during their growing season. How- 

 ever, the crop should be sprayed just after a shower of rain, 

 as it is such conditions as rain followed by sunshine that 

 causes blight. These spores increase so rapidly that the 

 whole field might be blighted down in two or three days if 

 the sun shines warmly. Therefore, I would say that the 

 whole idea of spraying is to protect the vine when the dis- 

 ease appears. 



If Paris green is added to the Bordeaux, the mixture 

 will adhere to the leaves, and, as it is a poison, no insects can 

 eat of it unless they are poisoned. Since it is a poison, it 

 should be handled carefully and kept away from children or 

 stock. 



Not only is the use of this mixture advisable for in- 

 sects and disease, but for the increased vigor of the plant 

 from its use. All sprayed plants are larger and darker green, 

 live longer, are hardier, and produce a better crop. I should 

 advise to always use at the rate of one-half pound of Paris 

 green to each fifty gallons of Bordeaux mixture. 



It is well to use a high pressure spray with fine nozzle, 

 so that all sides of the leaves are thoroughly coated. If the 



