16 



BULLETIN 550, U. S. DEPARTMENT OF AGRICULTURE. 



Table 5. — Spray mixtures used, methods and dates of application, and percentages of in- 

 festation in experimental plats, Phillips vineyard, North East, Pa., 1914. 





Dates sprayed 

 with set nozzles. 



Dates 



sprayed 



with 



trailers. 



Ar- 

 senate 

 of lead 

 (paste). 



Bordeaux mixture. 



Laun- 

 dry 

 soap. 



Nico- 

 tine 

 sul- 

 phate. 



Water. 



In- 



Plat No. 



Lime. 



Copper 

 sulphate. 



festa- 

 tion. 



I 



June 12, 26, and 

 July 12 





Lbs. 

 3 



3 

 3 



Pounds. 

 3 



3 

 3 



Pounds. 

 3 



3 

 3 



Pounds. 



Pints. 



Galls. 

 50 



50 

 50 



Per ct. 





5 2 



II 



June 26 and July 

 12 









4.5 



Ill 



June 26 



July 12 







7.2 



Check A. 









8.7 



IV 



June 26 and July 

 12 





3 

 3 

 3 



3 

 3 

 3 



3 

 3 

 3 



i 1 

 1 1 



> 1 



>i 



50 

 50 

 50 



9 5 



V 



June 26 



July 12 

 July 12 



5 5 



VI 



June 26 



17.9 



Check B. 





52 4 























wrsr 



jzr 



nr 



jzt 



J 



&4sr 



1 Last application only. 



The infestation in this vineyard had been very heavy the previous 

 season, but in 1914 it was light. Check plat B was much more heavily 



infested than the ad- 

 A/o/?7-*/ jacent sprayed plat; 



whereas this plat was 

 much more heavily 

 infested than check 

 plat A. While it is 

 probable that spray- 

 ing did reduce the in- 

 festation somewhat in 

 this plat and in the 

 one next to it, be- 

 cause of the wide va- 

 riation of infestation 

 in the unsprayed 

 checks, this can not be stated definitely. The similarity of results 

 in check plat A and the sprayed plats adjoining it indicates failure in 



control. 



Spraying Experiments in 1915. 



The season of 1915 was marked by extremely heavy rainfall during 

 the spraying season and during the month following. Spraying 

 operations were interrupted frequently or delayed by rain and as a 

 result spraying as a remedial measure was put to a very severe test. 

 However, when the final counts were made, all plats sprayed with 

 solutions containing arsenate of lead and soap and applied with 

 "trailers" showed a satisfactory reduction of infestation from a com- 

 mercial standpoint. The contrast in infestation between the sprayed 

 plats and others was commented on with astonishment at harvest 

 time by pickers who were ignorant that any remedial measures had 



Fig. 2.— Diagram showing arrangement "of experimental plats in Mr. M. 

 D. Phillip's vineyard, North East, Pa., 1914. Sprayed plats are 

 marked with Roman numerals, check plats with letters. (Original.) 



