22 



BULLETIN 550, U. S. DEPARTMENT OF AGEICULTUEE. 



Table 12. — Spray mixtures used and method and dates of application in experimental 

 plats, Bartlett vineyard, North East, Pa., 1916. 





Date, 

 sprayed. 



Arsenate 



Bordeaux mixture. 



Laundry 

 soap. 



Resin 

 fish-oil 

 soap. 



Potash 

 fish-oil 

 soap. 



Water. 



Method 



Plat No. 



of lead 

 (powder). 



Lime. 



Copper 

 sulphate. 



of appli- 

 cation. 



I.. 



July 22 



Aug. 12 

 Julv6,25 

 July 6,25 

 and Aug. 



12. 

 July 5,21 

 July 6,21 

 Julv5,21 

 July 5,22 



Pounds. 

 1J 



1* 

 1§ 



If 



2i 

 li 



14 



Pounds. 

 3 



3 

 3 

 3 



3 

 3 



Pounds. 

 3 



3 

 3 

 3 



3 

 3 



Pounds. 

 1 



Pounds. 



Pounds. 



Gallons. 

 50 



50 

 50 

 50 



50 

 50 

 50 

 50 



"Trail- 



II 



1 

 1 





ers." 

 Do. 



ni ... . 







Do. 



IV 



1 



1 

 1 

 1 





Do. 



v 







Do. 



IV 







Do. 



vn 







Do. 



VIII 



3 



3 





2 



Do. 











Table 13. — Percentage of infestation in experimental 



East, Pa., 1916. 



plats, Bartlett vineyard, North 





Number 

 of 



vines. 



Number 



of 

 clusters. 



Total, 

 berries. 



First brood. 



Second brood. 



Plat No 



Infested 

 berries. 



Infesta- 

 tion. 



Infested 

 berries. 



Infesta- 

 tion. 



Lower. 

 I 



20 

 20 

 20 

 20 

 20 

 20 

 20 



20 

 6 



20 

 6 



20 

 6 



532 

 424 

 415 

 389 

 390 

 411 

 460 



474 

 111 

 681 

 200 

 512 

 214 



17, 556 

 12, 720 

 12, 450 

 11, 281 

 11, 700 

 11, 508 

 12, 420 



15, 168 

 3,330 



18, 068 

 7,200 



14,336 

 6,S48 



1,708 



Per cent. 

 9.72 



2,970 



2,486 



6,913 



243 



81 



182 



10,909 



768 

 3,158 



724 



6,380 



67 



1,764 



Percent. 

 16.92 



II.. 



19.97 



Check A 



858 

 228 



6.64 

 2.02 



55.53 



Ill 



2.14 



IV 



.68 



V 



145 



1.26 



1.57 



Check B... 



79.72 



Upper. 

 VI .' 



320 

 717 

 199 

 452 

 69 

 263 



2.11 



21.53 



1.10 



6.27 



.48 

 3.84 



5.06 



Check VI 



94.83 



VII 



4.01 



Check Vn 



88.74 



VIII 



.47 



Check VIII 



25.76 







The final counts in this vineyard showed satisfactory results in all 

 plats on which two applications of arsenate of lead with soap had been 

 made (Plats III, V, VI, VII, and VI11). Where, in addition to 

 these two applications, a third application was made, directed solely 

 against the second brood, the percentage of infested fruit was slightly 

 reduced, but since the result was so satisfactory with two sprays (com- 

 pare Plat IV with III and V) an extra or third application was unneces- 

 sary. As an additional disadvantage, the fruit thus sprayed was badly 

 stained at harvest time. A single application made at the time when 

 the grape berries were just touching (Plat I) effected a marked re- 

 duction of infestation, as did a later single application directly solely 

 against the second brood (Plat II), but in both plats the results were 

 far from satisfactory. Any late application is open thus to objection 

 because of staining the fruit at the approaching harvest. Three ad- 

 hesives, laundry soap (Plat V), resin fish-oil soap (Plat III), and fish- 



