72 
THE GRAPE ROOT-WORM. 
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 
applica- 
tion. 
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 
92 
163 
246 
501 
11,950 
25 
55 
478 
217.2 
July 13,1908 
31 
109 
190 
330 
6,720 
25 
29 
268.8 
231,7 
July 19,1909 
41 
41 
74 
156 
4,020 
25 
35 
160.8 
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 
}Aug. 
2, 1907 
7 
10 
22 
39 
870 
25 
66 
34.8 
13.8 
June 22 
June 30 
jjuly 
13, 1908 
0 
5 
16 
21 
310 
25 
41 
12.4 
7.5 
July 2 
July 14 
}july 
19, 1909 
1 
7 
12 
20 
380 
25 
47 
15.2 
8.8 
CHECK (UNSPRAYED) PLAT-OLD CONCORD VINES. 
Aug. 
July 
July 
2, 1907 
13, 1908 
19, 1909 
52 
47 
35 
136 
139 
57 
213 
146 
91 
401 
332 
183 
8,810 
7,980 
4,370 
25 
25 
25 
71 
68 
352.4 
319.2 
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 
}Aug. 2,1907 
4 
13 
13 
30 
720 
25 
72 
28.8 
10.0 
June 22 
June 30 
jjuly 13,1908 
2 
13 
10 
25 
590 
25 
64 
23.6 
9.2 
July 2 
July 14 
Jjuly 19,1909 
0 
7 
14 
280 
25 
81 
11.2 
3.4 
CHECK (UNSPRAYED) PLAT— YOUNG NIAGARA VINES. 
Aug. 6, 1907 
July 15,1908 
July 19,1909 
32 
11 
3 
74 
18 
9 
77 
31 
15 
183 
60 
27 
4,590 
1,400 
570 
25 
25 
25 
49 
34 
51 
183.6 
56.0 
9.6 
93.6 
41.4 
4.7 
SPRAYED PLAT— YOUNG NIAGARA VINES. 
Formula same as above (5-5-3-50). 
J Aug. 6, 1907 
}july 15,1908 
jjulv 19,1909 
0 
2 
1 
3 
70 
25 
35 
2.8 
0 
1 
0 
1 
30 
25 
36 
1.2 
1 
4 
7 
12 
240 
25 
51 
9.6 
