CONTROL OF THE GRAPE-BERRY MOTH. 
31 
applied safely. However, the combination of arsenate of lead and 
soap alone produced slight burning of foliage in 1916. (Bartlett 
vineyard, Plat VII.) 
No serious staining of fruit occurred except when the second- 
brood spray was applied in August in 1916. This was much reduced 
by using the arsenate of lead and soap with lime instead of with 
Bordeaux mixture. 
Method of Application. 
The first season's experiments clearly demonstrated the difficulty 
in covering grape clusters by the " set-nozzles" applications. This 
was particularly inadequate at the last application, at which time 
the foliage is very heavy, and pressure up to 250 pounds was not 
effective. The use of " trailers" on a few plats for the last appli- 
cation suggested the complete change of method which followed the 
next season. 
A specific demonstration of the inadvisability of depending on 
"set nozzles" as a means of applying spray was shown in 1915 by 
the contrast between Plats I and X in the Miller and Carlburg vine- 
yard. 
The necessity of using "trailers" was so satisfactorily established 
in the first two seasons that during 1916 "set nozzles" were not used 
in both applications in any plats. However, in the Moorhead vine- 
yard, Plat IV, and in the Southwick vineyard, Plat IV, "set nozzles" 
were tried for the first application. In the former, at the time of 
the first application, the results were reasonably satisfactory, 
although not the best. In the latter vineyard the foliage was very 
heavy when "set nozzles" were used, and the failure to cover the 
clusters with spray was obvious. The reduction of infestation that 
resulted should be credited largely to the last application, which 
was made with "trailers." 
The relative efficiency of "set nozzle" and "trailer" methods of 
application and a combination of these methods is shown in Table 22. 
Table 22. — Relative efficiency of "trailer" and "set nozzle" methods of application. 
(Treatments common to all plats: Arsenate of lead, 3 pounds paste or lh pounds powder; laundry 
soap, 1 pound; Bordeaux mixture (3-3-50) applied after falling of blossoms and when grape berries 
were just touching.) 
Method of application. trSe? 
Num- 
ber of 
vine- 
yards. 
Num- 
ber of 
plats. 
Infested grape berries. 
Best 
plat. 
Adja- 
cent 
check. 
Poor- 
est 
plat. 
Adja- 
cent 
check. 
Aver- 
age of 
all 
plats. 
Aver- 
age of 
all 
checks. 
'Trailers," 2 applica- 
tions 1915, 1916 
'Set nozzles," 1 appli- 
cation; "trailers," 1 
application 1916 
'Set nozzles," 2 applica- 
tions 1915 
Per ct. 
6.61 
20.41 
Per ct. 
50.43 
38.43 
28.80 
Per ct. 
8.43 
19.13 
20.41 
Per ct. 
75.16 
65. 65 
28.80 
Per ct. 
4.12 
12.87 
20.41 
Per ct. 
50.03 
52.04 
28.80 
