72 



THE GKAPE ROOT-WOKM. 



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

 occurrence of eggs in sprayed and unsprayed plats in Davidson vineyard for 1907, 1908, 

 and 1909, North East, Pa. 



CHECK (UNSPRAYED) PLAT— YOUNG CONCORD VINES. 



Date of 



When 

 examined. 



Number of egg clusters found. 



Estimated 

 number 

 of eggs. 



Num- 

 ber of 

 vines. 



Num- 

 ber of 

 canes. 



Average num- 

 ber of eggs. 



Large. 



Me- 

 dium. 



Small. 



Total. 



Per 

 vine. 



Per 

 cane. 





Aug. 2,1907 

 July 13,1908 

 July 19,1909 



92 

 31 

 41 



163 

 109 

 41 



246 

 190 



74 



501 

 330 

 156 



11,950 

 6,720 

 4,020 



25 

 25 

 25 



55' 

 29 

 35 



478 



268.8 



160.8 



217.2 

 231.7 

 114.8 



SPRAYED PLAT— YOUNG CONCORD VINES. 

 Formula: 5 lbs. blue vitriol (copper sulphate), 5 lbs. lime, 3 lbs. arsenate of lead, 50 gallons water. 



July 15 



July 23 



June 22 



June 30 



July 2 



July 14 



JAug. 2, 1907 



7 



10 



22 



39 



|july 13,1908 







5 



16 



21 



jjuly 19,1909 



1 



7 



12 



20 



870 



25 



66 



34.8 



310 



25 



41 



12.4 



380 



25 



47 



15.2 



13.8 

 7.5 



CHECK (UNSPRAYED) PLAT— OLD CONCORD VINES. 



Aug. 



2, 1907 



5. 



136 



213 



401 



July 



13, 1908 



47 



139 



146 



332 



July 



19, 1909 



35 



57 



91 



183 



8,810 



25 



69 



352.4 



7,980 



25 



71 



319.2 



4,370 



25 



68 



174.8 



127.6 

 112.3 

 64.2 



SPRAYED PLAT— OLD CONCORD VINES. 

 Formula same as above (5-5-3-50). 



July 



15 



July 



23 



June 



22 



June 



30 



July 



2 



July 



14 



JAug. 2,1907 



4 



13 



13 



30 



|july 13,1908 



2 



13 



10 



25 



|july 19,1909 







7 



7 



14 



720 



25 



72 



28.8 



590 



25 



64 



23.6 



280 



25 



81 



11.2 



10.0 

 9.2 

 3.4 



CHECK (UNSPRAYED) PLAT— YOUNG NIAGARA VINES. 





Aug. 6, 1907 



32 



74 



77 



183 



4,590 



25 



49 



183.6 



93.6 





July 15,1908 



11 



18 



31 



60 



1,400 



25 



34 



56.0 



41.4 





July 19,1909 



3 



9 



15 



27 



570 



25 



51 



9.6 



4.7 



SPRAYED PLAT— YOUNG NIAGARA VINES. 

 Formula same as above (5-5-3-50). 



July 



15 



July 



23 



June 



22 



June 



30 



July 



2 



July 



14 



Aug. 6, 1907 

 July 15,1908 

 •July 19,1909 







2 



1 



3 



70 



25 



35 



2.8 







1 







1 



30 



25 



36 



1.2 



1 



4 





12 



240 



25 



51 



9.6 



2.0 



4.7 



