8 BULLETIX 837, TJ. S. DEPARTMENT OF AGRICULTURE. 
was applied when the grapes touched in the clusters, but before the 
clusters were tight enough to prevent the spray material from being 
driven between the grapes. This stage of grape growth usually oc- 
curs from 3 to 4 weeks after bloom. This second spraying was 
designed to kill the late hatching first-brood larva? and to remain 
on the grapes to be effective when the second-brood larva? hatched. 
The third spraying was timed in each case to precede immediately the 
hatching period of the majority of second-brood larvae. 
METHOD OF APPLICATION. 
All spraying was done by the hand or trailer method in which 2 
hose lines of from 20 to 50 feet trail behind the sprayer, and the 
spray material is delivered through short spray rods and angle noz- 
zles, directed by hand as in tree sjDraying. Variations in this method 
will be discussed later. Sufficient pressure was maintained to drive 
the spray well into the clusters, but the amount of pressure varied 
from 125 to 225 pounds in different vineyards. The best pressure to 
maintain will vary somewhat with the vineyards, but the writers 
believe that from 175 to 225 pounds usually will be found most 
efficient. Xozzles set at an angle are absolutely necessary for efficient 
work, and it was found- that nozzles set at angles of 45° allowed 
more freedom of handling than those set at 90°. A nozzle aperture 
of iVinch was most commonly used, but the most efficient size was 
found to vary with the vineyard and other local conditions. 
WEATHER CONDITIONS 1 AFFECTING SPRAY RESULTS. 
The season of 1916 was about normal in all respects except for an 
unusually dry period during July and August which was favorable 
for spraying and for spray material adhering. These same condi- 
tions were likewise favorable for the development of an unusually 
large second brood of worms. September and October were warm 
and dry, conditions also favorable to extensive berry moth injury 
as shown in the uniformly heavy infestation in the checks (Table IV). 
In 1917 conditions were decidedly unfavorable for spraying opera- 
tions. Both the first and second applications were interfered with 
by rain and closely followed by showers of varying intensities. In 
July the total rainfall was but 0.16 inch, but this came between the 
first, and second spray applications. The maturing of first-brood 
larva? was favored by an exceedingly hot and dry period from July 28 
to August 6 and a subsequent heavy hatching of second-brood 
larva? followed. September was 3.3° below normal in temperature 
and slightly below in precipitation, while October was 8.3° below 
normal with 3.79 inches of rainfall above normal. These unfavorable 
1 Weather records from the I". S. Weather Bureau Station at Sandusky. Ohio. 
