THE GRAPE-BERRY MOTH. 



61 



Table XXVIII. — Progress of infestation of fruit by larvx of the grape-berry moth in 

 experimental plats. Vineyard of Mr. W. S. Wheeler, North East, Pa., 1909 — Contd. 



FIRST COUNT OF INFESTED BERRIES, MADE ON JULY 25. 



Plat No. 



Date of spray application. 



Spray formula. 



Number 

 of appli- 

 cations. 



Number 

 of vines 

 exam- 

 ined. 



Number 



ofinfested 



berries. 



Va Vb 





None 



None. 

 None. 

 None. 

 None. 



25 

 25 

 25 

 25 



34 



Do 



Do 



Do 



do 



do 



do..., 



do 



do 



do 



28 



21 

 19 



SECOND COUNT OF INFESTED BERRIES, MADE ON SEPTEMBER 21 TO 24. 



Va Vb 





None 



None. 

 None. 

 None. 

 None. 



25 

 25 

 25 



25 



1,574 



Do 



. ..do 



do 



890 



Do 



Do 



do 



.do 



do 



do 



468 

 1,168 











The counts were made July 25 and September 21 to 24. The 

 infestation this season, as in 1907 and 1908, was heavier on the south 

 side of Plat I and on the east end of the east section and became 

 lighter toward the north side and west end of the vineyard, a condi- 

 tion which existed throughout the three seasons. 



When the crop was harvested it was found that there was practic- 

 ally no difference in weight of fruit per acre on the sprayed and the 

 unsprayed vines. Taking the vineyard as a whole the infestation 

 was very much lighter than in either of the preceding seasons. (See 

 Table XXIX, showing percentage of infected berries on fruit from 25 

 vines in each of the sprayed and the unsprayed plats.) 



Table XIX. — Percentage of grape berries infested by larvae of the grape-berry moth on 

 25 vines in sprayed and unsprayed plats. Vineyard of Mr. W. S. Wheeler, North East, 

 Pa., 1909. 



SPRAYED. 



Plat 

 No. 



Dates sprayed. 



Num- 

 ber of 

 times 

 sprayed 



Formula. 



Num- 

 ber of 

 vines 

 exam- 

 ined. 



Total 

 number 

 of 

 clus- 

 ters. 



Aver- 

 age 

 num- 

 ber of 

 ber- 

 ries 

 per 



Num- 

 ber of 

 infest- 

 ed 

 ber- 



Total 



number 



of 



ber- 

 ries. 



Per- 

 cent- 

 age of 



in- 

 fested 



ber- 



Date 



clusters 



were 



examined. 















clus- 

 ter. 





nes. 







1909. 





















I... 

 II.. 



June 8, 28, 



July 9. 

 do ... 



3 



3 

 2 

 2 



5-5-3-50 



5-5-3-50 



5-5-3-50 



5-5-3-50 



25 



25 

 25 

 25 



1,512 



1,242 

 1,203 

 1,288 



38 



38 

 38 

 38 



750 



396 

 554 

 390 



57,456 



47, 196 

 49,514 

 48, 944 



1.30 



.84 



1.12 



.79 



Sept. 21-24 



Do. 

 Do. 

 Do. 



III. 

 IV. 



June 28, July 9. 

 do 





UNSPRAYED. 



Va 

 Vb 

 Va 

 Vb 

 Va 

 Vb 

 Va 

 Vb 



Unsprayed 



None.. 



....do 



. . .do . . 



....do 



...do.. 



do 



...do.. 



None.. 

 ....do. 

 ....do. 

 ....do. 



25 



1.102 



38 



1,574 



42,256 



3.72 



25 



994 



38 



890 



37,772 



2.36 



25 



747 



38 



468 



26, 562 



1.77 



25 



1,182 



38 



1,168 



44,916 



2.60 



Sept. 21-24 

 Do. 

 Do. 

 Do. 



