POTATO DISEASES AND THEIR REMEDIES. 



21 



As the crop develops the potato bugs appear and are to be 

 poisoned promptly. Where Paris green or other arsenites are 

 used care needs to be taken to prevent the burning of -the foliage 

 already described. We apply these poisons with a spray pump 

 in water and avoid all danger by mixing the poison with lime. 

 We slack 2 pounds of stone lime for each pound of the poison, 

 stir the poison into the lime while the lime is hot and let stand 

 several hours before using. 



SPRAVKU. NOT Sl'RAVEU. 



Figure 4. Showing the gain from Bordeaux mixture In checking insect injuries. 

 There was practically no blight on this Held, the gain resulted chiefly from the fact 

 that the Bordeaux mixture kept the sprayed rows free from flea beetles and grass- 

 hoppers. It also reduced. the amount of tip-burn. 



Closely following the common potato bug comes that other 

 pest — the flea-beetle — which refuses to be poisoned. Fortu- 

 nately it has a great repugnance for Bordeaux mixture. Con- 

 sequently we begin the use of that mixture, with poison added, 

 early enough to stop his work. The middle of July with us 

 suffices to forestall both flea-beetle and early blight, and we start 

 ■vvith the combination Bordeaux-Paris-green mixture about that 

 date. Often with late main crop potatoes a later beginning is 

 equally efficacious. If in any doubt, however, begin to spray 



