36 
THE HOP APHIS IN THE PACIFIC REGION". 
The cost of stripping the vines preliminary to spraying will be from 
$1.80 to $2 per acre. 
The cost of spraying for the hop aphis, although apparently great, 
is nothing compared to the losses which result from neglect to spray 
for this insect. 
Thorough spraying is, then, a good business policy and should be 
carefully done by all commercial hop growers. 
CULTURAL METHODS. 
CLEAN CULTURE. 
Suckers growing between the rows and vines growing over fences 
and near-by trees usually have much dense foliage, due to the growth 
^m 
^way*?" 
Fig. 8.— Short-pole hopyard, showing dense foliage around base of vines, which harbors the hop aphis. 
(Original.) 
of several plants upon a limited area, and form an ideal breeding place 
for the aphides. Such plants may form a constant source of infesta- 
tion and should be promptly removed. 
STRIPPING THE VINES. 
One of the most important cultural methods now in use is stripping 
the vines to a point about 4 feet above the ground (fig. 8). This 
removes the suckers and dense foliage, which protect and foster the 
aphides, from around the base of the vines. Experiments show that 
