﻿40 BULLETIN 19, U. S. DEPAETMENT OP AGEICULTUEE. 



to the underside of the grape leaves by holding a short rod, one end 

 connected to the spray hose and the free end carrying a large nozzle 

 of the cyclone type directed upward at right angles to the rod. (See 

 PL III, fig. 1.) Effective results in killing the nymphs by this method 

 appeared to depend more upon the person manipulating this rod than 

 upon the type of sprayer used or the number of pounds of pressure 

 applied, providing the pressure was not allowed to drop below 75 

 pounds. Of course with the higher pressure larger areas can be cov- 

 ered in a given time than with the low pressure. Yet the most effec- 

 tive work done in the control of this pest coming under observation 

 of the writer was accomplished with a tractor machine, with a pressure 

 fluctuating between 70 and 125 pounds, in the hands of a very thorough 

 vineyardist. This feature is emphasized here because the small vine- 

 yardist, being under the impression that an expensive high-pressure 

 spray outfit is necessary, is frequently deterred in attempting to con- 

 trol this pest, whereas the most important thing is care in the direction 

 of the spray so that the greatest number of nymphs will be drenched, 

 and this can be done with the same tractor machine that is used for 

 applications against the grape rootworm. On the other hand, it is 

 doubtless much more economical for the vineyardist with large areas 

 to cover to have larger high-pressure outfits, since with them two or 

 even more leads of hose may be used (PL III, fig. 2) , making it possible 

 to cover large areas in a very short time. This is highly desirable, 

 since there are only about 8 to 12 days during which the maximum 

 number of nymphs is present upon the foliage. 



In order to lessen the time required to make the application and 

 to reduce the cost, many attempts have been made to apply the spray 

 to the underside of the grape foliage by means of a fixed nozzle ar- 

 rangement instead of making the application by the trailer method 

 described above. The chief difficulty arising in the use of a fixed- 

 nozzle arrangement is that such a device applies no more liquid to 

 a vine carrying a large amount of dense foliage than to one carrying 

 a moderate amount of more widely spaced f oliage ; hence it frequently 

 happens that much more spray than is necessary is applied to the 

 vine carrying light foliage and not enough is applied to the one carry- 

 ing dense foliage. 



The types of fixed-nozzle arrangement are being tried out in the 

 vineyards of the Lake Erie Valley. One of these was for a tractor or 

 a gasoline-engine power sprayer, and was devised and used by Mr. 

 F. Z. Hartzell. 1 The other arrangement was used for a steam-engine 

 power sprayer. (PL II, fig. 2.) Both of these arrangements are 

 reported to have given fairly satisfactory results in killing nymphs 

 where the foliage was not very dense. In most cases, however, suc- 



i Bui. 344, N. Y. (Geneva) Exp. Sta., Pis. I-IV. 



