HARVESTING 181 



sary to use a second application a week or two after the 

 first one. If rain follows within a few hours after the first 

 application it is best to respray at once. Paris green may 

 be added to the Bordeaux mixture and the potatoes can 

 thereby be sprayed for the prevention of blight and insects 

 at the same time. 



Instead of Paris green, arsenate of lead may be added to 

 the Bordeaux mixture at the rate of 3 pounds to 50 gallons 



Fig. 99. A Wisconsin potato field. Note the quantity of potatoes. 



of the solution. The arsenate of lead sticks to the potato 

 leaves better than does Paris green, particularly in damp 

 weather. 



Harvesting. Potatoes should be harvested when in 

 proper condition for marketing or storing away for winter 

 use. The proper condition is indicated by the drying 

 up of the vines. The vines of ripe potatoes when pulled 

 free themselves from the tubers. Unripe potatoes adhere 



