Xkw Yokk AoRTCiTi/ruKAL Exn:RniENT Station. 381 



If the automatic leaf-hopper sprayer is used, the nozzles must he 

 set at the proper angles on the booms. There is no fixed rule. 

 Each nozzle must be set so as to cover the under sides of the most 

 foliage. Usually the nozzle on the lower boom is set to throw 

 the spray vertically, since this boom can swing under the vines 

 farther than the others. The nozzles on the middle and top booms 

 must be set at slightly different angles. The height of the vines, 

 the manner of trimming and the direction of the wind must all 

 be taken into consideration: One should examine the under sides 

 of the sprayed leaves from time to time to see that the nozzles are 

 properly adjusted. 



(6) Drive slow if foliage is dense. — If one is using a traction 

 sprayer (one in which the power is secured by gearing attached 

 to the wheels of the sprayer) it should have a pump of sufficient 

 capacity to maintain a pressure of 150 lbs. per sq. in., using six 

 large apertured nozzles and driving slowly. With gasoline en- 

 gine sprayers it is necessary to have an engine and pump of 

 sufficient capacity to carry the required pressure with six large 

 nozzles. 



Spraying as directed one would use nearly 150 gallons of spray 

 material per acre where the foliage is dense. Where vines are 

 weak or young and the foliage is not dense, one can secure good 

 results by using discs with slightly smaller apertures, thus using 

 less spray per acre. One's judgment must govern him in the 

 use of material economically. 



With the use of 150 gallons of material per acre, using the nico- 

 tine preparations at the present prices, it would cost about $1.25 

 per acre for material to control the grape leaf-hopper for a 

 season. 



