REMEDIAL MEASURES. 



73 



Table XXVII. — Effect of poison spray against the grape root-worm as shown by occur- 

 rence of larvse at roots of vines in sprayed and unsprayed plats in Davidson vineyard 

 in 1907, 1908, and 1909, at North East, Pa. 



DIGGINGS MADE IN SUMMER OF 1907. 



Date of examination. 



Number 

 of vines. 



Variety and age of 

 vines. 



Number of larvae. 



Un- 

 sprayed 

 plat. 



Sprayed 

 plat. 



<=!eptember 5, 1907 



1 

 1 

 1 



Young Concord. . . 



Old Concord 



Young Niagara 



92 



91 



6 



6 

 1 

 



Do 



Do 





DIGGINGS MADE IN SUMMER OF 1908. 



August 26, 1908. 



August 25, 1908- 



Do 



Young Concord. . . 



214 



40 



Old Concord 



86 



4 



Young Niagara 



58 



5 



DIGGINGS MADE IN SUMMER OF 1909. 



September 8-9, 1909 



5 

 5 

 5 



Young Concord. .. 



Old Concord 



Young Niagara.... 



39 

 13 





 

 



September 10-15, 1909 . 



September 11-15 1909 





Table XXVIII. 



-Davidson vineyard. Effect of spray applications on the crop yield 

 for the seasons 1908 and 1909 at North East, Pa. 



FOR SEASON OF 1908. 



Year. 



Variety and age of 

 vines. 



Treatment. 



Plat 

 area. 



Plat 

 yield. 



Value per 

 basket. 



Value per 

 acre. 



Spray 



benefit 



per acre. 



1908 

 1908 

 1908 

 1908 

 1908 

 1908 



Young Concord 



do 



Old Concord 



do 



Young Niagara 



do 



Sprayed... 



Unsprayed 



Sprayed 



Unsprayed 



Sprayed 



Unsprayed — 



Acre. 



t 



if 



4 

 1 



Lb.baskets 

 101.8 

 81.8 

 502.0 

 455.0 

 231.4 

 150.4 



Cents. 

 13 

 13 

 13 

 13 

 9 

 9 



$26. 26 

 21.06 

 86.97 

 78.91 

 62.37 

 40.50 



$5.20 



8.06 



21.87 





FOR SEASON OF 1909. 



i9og 



1909 

 1909 

 1909 

 1909 

 1909 



Young Concord. 



do 



Old Concord 



....do 



Young Niagara. 

 do 



Sprayed 



Unsprayed.. 



Sprayed 



Unsprayed.. 



Spraj'ed 



Unsprayed.. 



435.8 

 217.0 

 ,039.0 

 836.0 

 158. 2 

 85.0 



$95. 70 

 47.74 

 152. 35 

 112. 65 

 132. 72 

 71.40 



$47. 96 



39.70 

 "6i.'32' 



The effect of the spray on egg deposition was obtained by stripping 

 all of the loose bark from 25 consecutive vines in the sprayed portion 

 and also in the check rows, making an actual count of the number of 

 egg clusters deposited on an equal number of consecutive vines in the 

 sprayed and unsprayed plats. This has proved to be one of the best 

 ways to determine the immediate direct effect of spray applications. 

 These examinations were made at a time, determined by careful 



