CONTROL OF THE GRAPE-BEERY MOTH. 
37 
The umbrella system with the canes bent down from the upper 
wire to the lower presented a difficulty in spraying similar to that of 
the Chautauqua system, although it seemed slightly easier to spray. 
The high-renewal system was much more difficult to spray owing 
to the tendency of the rods to catch in the numerous upright shoots. 
Summary of Important Factors in Spraying Practice. 
The most important factors in spray practice to control the grape- 
berry moth, shown by the final counts in 28 of the 49 experimental 
plats of three years, are summarized briefly in Table 24. Factors of 
minor importance such as a complete comparison of adhesives and 
value of nicotine sulphate are omitted. In addition, the plats in the 
experiment in the Phillips vineyard, 1914, because of the erratic 
infestation, and the plats in the Miller and Carlburg vineyard, 1915, 
which were affected by rain, are excluded. 
Table 24. — Relative efficiency of spraying measures tried. 
Spray mixture, method of application, and spray schedule fol- 
lowed. 
Years 
tried. 
Number 
of 
sprayed 
plats. 
Infested fruit . 
Average 
in 
sprayed 
plats. 
Average 
in adja- 
cent un- 
sprayed 
checks. 
I. Arsenate of lead, paste, 3 pounds, or powder, \\ pounds; 
laundry soap, 1 pound; Bordeaux mixture, 3-3-50. Ap- 
plied with "trailers" immediately after blossoms had 
fallen and again when grape berries were just touch- 
ing (or about 2 weeks later) 
II. Same as I except arsenate oi lead omitted 
III. Same as I except adhesive omitted 
IV. Same as I except Bordeaux mixture omitted 
V. Same as I except arsenate of lead increased to 5 pounds 
(paste) or 2\ pounds (powder) 
VI. Same as I except resin fish-oil soap used instead of laun- 
dry soap, 1 pound 
VII. Same as I except fish-oil soap (without resin) used in- 
stead of laundry soap, 2 pounds 
VIII. Same as I with addition of a third application 5 weeks 
after first 
IX. Same as I (including only the plat adjacent to VI) 
X. Same as I except first application omitted 
XI. Same as I except " set nozzles " used in first application 
instead of " trailers " 
XII. Same as I except "set nozzles" used in both applica- 
tions instead of " trailers" 
XIII. Same as I except adhesive omitted and "set nozzles" 
used in both applications instead of "trailers" 
1915, 1916 
1915 
1915 
1916 
1915, 1916 
1916 
1915,1916 
1916 
1916 
1916 
1916. 
1915 
1914 
Per cent. 
4.12 
33.31 
21. 05 
4.01 
3.34 
2.14 
3.95 
.68 
1.57 
18.71 
12.87 
20.41 
26. 70 
Per cent. 
50.03 
28.80 
28.80 
88.74 
54.90 
55.53 
42.84 
67.52 
79.72 
51.29 
52.04 
28.80 
31.80 
This table shows that both arsenate of lead and soap are essential 
factors in the spray mixture, while Bordeaux mixture is of little 
importance. An increase in the amount of arsenate of lead is usually 
of little value, and variation among the three kinds of soap used is not 
an essential consideration. Two applications effect a practically 
satisfactory control so that the advantage of a third application is 
insignificant. The omission of the first application, or making it 
