Control Measures 215 



these must be protected by subsequent applications. 

 These applications should be continued as long as growth 

 of the vine takes place. Even when the vines cover the 

 space between the rows and driving through will injure 

 them, the spraying must be done. Less loss will result 

 from injured vines than from rotted tubers. On loamy 

 ground, the injury to the vines is not so great as one would 

 think. Some ingenious farmers have devised a means of 

 pushing the vines away from the wheels by attaching rake 

 teeth on each side of each wheel. Manufacturers of 

 spraying machinery should be able to devise some means 

 of overcoming this objection to spraying. 



From five to eight applications, depending upon weather 

 conditions, should be made during the season. The first 

 should be given when the plants are six to eight inches 

 high or when a poison is applied to kill the bugs. For 

 the early applications 50 to 75 gallons of mixture to the 

 acre will be sufficient, but later in the season it will re- 

 quire 100 gallons or more. Enough should be applied to 

 do a good piece of work even though it takes 150 gallons. 

 The operator should determine this. Nozzles capable of 

 delivering this amount of liquid as a mist must be the 

 only kind employed, although pressure has much to do 

 with fineness of the mist. From 70 to 80 pounds of 

 pressure will make a fine mist with vermorel nozzles if 

 there are not too many used at a time, while it will take 

 100 to 150 pounds of pressure to get a good mist w^ith an 

 equal number of disk nozzles. But the vermorels do not 

 have the capacity that disk nozzles do and more are re- 

 quired to do the same work. One disk nozzle will do 

 good work at first, but two should be employed later on 

 and then should be so adjusted that the spray is directed 

 at an angle rather than straight down upon them. The 



